An integrated construction method for anti-buoyancy anchors and waterproof layers

Abstract

This invention discloses an integrated construction method for anti-buoyancy anchors and waterproof layers, belonging to the field of underground engineering geotechnical anchoring technology. Addressing the shortcomings of existing technologies, such as the susceptibility of anti-corrosion coatings to scratches during construction, the formation of permanent weak interfaces in the free section isolation layer, and the unreliability of traditional biodegradable materials relying on microbial degradation, this invention applies an anti-corrosion primer coating to the entire length of the anchor, while only the free section is fitted with a hydrolytically degradable fiber woven bag filled with a buffer dry powder material. The anchor section is then directly grouted. The bag uses a blend of polyglycolic acid and polylactic acid-glycolic acid copolymer fibers, and the dry powder material contains river sand, fly ash, a small amount of cement, and an alkali hydrolysis accelerator. Controllable hydrolysis is achieved within 12-24 months through internal and external dual alkali triggering. This invention provides a buffer and protective coating during construction, forms a non-Newtonian fluid energy-absorbing and shock-absorbing layer during use, and completely eliminates the organic interface after degradation, ensuring that the pull-out resistance of the anchor section is unaffected. The free section achieves long-term waterproofing and corrosion protection, with low overall cost, simple construction, and compliance with current specifications.

Description

Technical Field

[0001] This invention relates to the field of geotechnical anchoring technology in underground engineering, specifically a method for integrating anti-buoyancy anchors and waterproof layers. Background Technology

[0002] Anti-buoyancy anchors, as one of the main anti-buoyancy measures for underground structures in building engineering, are widely used in permanent structures such as underground garages and basements. Because underground structures need to serve for a long time, anti-buoyancy anchors must meet corrosion and waterproofing requirements while ensuring sufficient pull-out bearing capacity. Existing anti-buoyancy anchor technologies mainly employ methods such as galvanizing the anchor body surface, coating with epoxy resin, and grouting for corrosion protection. However, under long-term loads and corrosive groundwater, the grouting material is prone to developing cracks, allowing corrosive media to contact the anchor body through these cracks and gradually corrode the anchor body.

[0003] Currently, the corrosion and waterproofing treatment of anti-buoyancy anchors at the junction of the base slab and the cushion layer typically involves first constructing the anchor, then the cushion layer, and finally, after the reinforcing steel is exposed, applying waterproof coating, waterproof membrane, a waterproof layer, and multiple protective layers in sequence. This construction process is not only complex and difficult to implement, but also struggles to fully guarantee the effectiveness of corrosion and waterproofing. Furthermore, for the corrosion protection of the free section of the anchor, existing technologies mainly rely on coatings or sleeves, lacking an effective impact-resistant buffer protective layer. Under dynamic loads such as soil deformation or earthquakes, the anti-corrosion coating is easily damaged, leading to corrosion failure.

[0004] To address the aforementioned issues, existing technologies have developed a solution using a bag-like anti-corrosion anchor bolt, which creates a sealed protection by encasing the lower section of the bolt. However, this full-length encapsulation method artificially creates a smooth interface with low bond strength in the anchoring section, significantly reducing the bond strength between the reinforcement and the grout, easily leading to overall anchor bolt slippage and failure. YB / T4659-2018 "Technical Specification for Anti-buoyancy Anchor Bolts" Article 4.2.3 clearly states that anti-corrosion materials such as epoxy coatings significantly reduce the bond strength between the reinforcement and the soil, and specific tests must be conducted before use to determine the actual bond strength and anchor efficiency. Therefore, how to ensure anti-corrosion and waterproofing effects without weakening the pull-out bearing capacity of the anchoring section is a pressing technical problem to be solved in this field. Summary of the Invention

[0005] This invention overcomes the shortcomings of existing technologies and proposes an integrated construction method for anti-buoyancy anchors and waterproof layers. This method, through segmented design, constructs a biodegradable flexible buffer-anti-corrosion composite layer in the free section of the anchor, and peels off the wrapping layer in the anchoring section and uses conventional grouting for anchoring. This effectively protects the anti-corrosion coating in the free section from impact damage and ensures reliable bonding between the anchoring reinforcement and the grout, achieving synergistic optimization of anti-corrosion and waterproofing performance and load-bearing capacity.

[0006] This invention is achieved through the following technical solution: This invention proposes an integrated construction method for anti-buoyancy anchors and waterproof layers, comprising the following steps: S1. Anchor bolt body preparation: The surface of the anchor bolt body is derusted, and an anti-corrosion primer is applied to the entire length of the anchor bolt body. S2. Preparation and filling of free segment bags: The buffer dry powder is filled into a hydrolyzable and degradable fiber woven bag, and then heat-sealed to obtain a filled bag. The buffer dry powder contains, by weight, 55-65 parts river sand, 18-25 parts fly ash, 3-6 parts cement, 3-5 parts bentonite, 1-2 parts starch, 0.3-0.5 parts superabsorbent polymer (SAP) resin and 1-3 parts degradation accelerator. After being moistened, the buffer dry powder exhibits typical shear thickening (non-Newtonian fluid) characteristics. Therefore, it deforms slowly under normal conditions and is flexible and does not scratch the coating when flowing. When subjected to impact, vibration, or rapid extrusion, it can instantly thicken and harden, absorbing energy. It absorbs soil deformation and seismic forces to prevent sand and gravel on the borehole wall from directly extruding and scratching the primer, releases stress concentration in the free section, and protects the anchor rod and joint from water damage.

[0007] The hydrolyzable and degradable fiber woven bag is made of a blend of polyglycolic acid fiber and polylactic acid-glycolic acid copolymer fiber. S3. Bag installation: Insert the filling bag and fix it to the corresponding position of the free section of the anchor rod; The free section is the section of the anchor rod that does not require anchoring force, while the anchoring section that requires pull-out resistance is not fitted with a sleeve. The epoxy / polyurea primer dry film is ≥300μm, providing the first continuous anti-corrosion and waterproof barrier. However, the coating itself is brittle and easily scratched by sand and gravel, so it must rely on external bag protection. The dry powder filling of the bag is controlled at 70% to 80% of the bag volume, leaving gaps to allow SAP to absorb water and expand, and particles to shift, maintaining non-Newtonian fluid characteristics. The dry powder is sealed and stored to avoid premature moisture and solidification. Only the free section is bagged, and the anchoring section is bare. The anchoring section is not bagged or isolated. The steel bar + primer is directly bonded to the grouting body, ensuring that the pull-out resistance of the anchor rod is entirely provided by the steel bar-grouting body-soil interface. Since the free section does not require bonding force, it only needs anti-corrosion, buffering, and friction reduction. The bag forms a flexible protective layer in this section and does not affect the structural stress.

[0008] S4. Drilling and Anchor Installation: Drill holes at predetermined locations, clean the holes, and then place the treated anchor rods into the drilled holes. S5. Grouting of anchorage section: Inject cement grout into the anchorage section and cure it after grouting is completed; S6. Waterproofing treatment at joints: A waterproof structure is installed at the connection joint between the anchor rod and the base plate, and the base plate concrete is poured.

[0009] Preferably, in step S2, the mass ratio of polyglycolic acid fiber to polylactic acid-glycolic acid copolymer fiber in the hydrolytically degradable fiber woven bag is 60-70:30-40. In polylactic acid (PLGA)-glycolic acid (PGA) copolymer fibers, the molar ratio of lactic acid units to glycolic acid units is 65-75:25-35.

[0010] PGA has a fast hydrolysis rate and high strength, and is responsible for structural support during construction. PLGA degrades more gently and has good toughness. To control the overall degradation cycle, in order to ensure sufficient strength to withstand the pressure of lowering and grouting, as well as uniform hydrolysis in an alkaline environment, and to prevent sudden breakage and long-term corrosion, the ratio of PGA:PLGA in the blended fiber is controlled to be 60~70:30~40. Preferably, in step S2, the degradation promoter is calcium oxide or calcium hydroxide; The superabsorbent resin is added at 0.2% to 0.5% of the cement mass, in a dry manner; the filling amount of the buffer dry powder is 70% to 80% of the bag volume.

[0011] Preferably, in step S1, the anti-corrosion primer is an epoxy anti-corrosion primer or a polyurea anti-corrosion primer, and its dry film thickness is not less than 300 μm.

[0012] Preferably, in step S2, the hydrolyzable and degradable fiber woven bag is a woven bag or a non-woven bag, with a tensile strength of not less than 20 MPa and an elongation at break of not less than 200%.

[0013] Preferably, in step S2, the buffer dry powder should be used up within 24 hours after preparation, and the filling bag should be kept dry and sealed before installation.

[0014] Preferably, in step S3, both ends of the bag are fixed to the anchor rod body by corrosion-resistant cable ties or stainless steel clamps, with at least two fixing components at each end.

[0015] Preferably, in step S5, the water-cement ratio of the cement grout is 0.40 to 0.45, the grouting pressure is 0.5 to 1.0 MPa, and the 28-day compressive strength of the grout body is not less than 30 MPa.

[0016] Preferably, after the S5 grouting is completed, the dry powder material inside the free section bag is moistened by groundwater infiltration, forming a non-Newtonian fluid buffer layer with shear thickening properties. Under the alkaline environment created by the degradation accelerator inside the bag and the cement slurry outside the bag, the bag gradually hydrolyzes and degrades within 12 to 24 months, forming water-permeable channels.

[0017] The beneficial effects of this invention compared to the prior art are as follows: This invention is the first to integrate alkali-triggered hydrolytic degradation of fiber bags, shear-thickening dry powder buffer system, internal and external dual degradation mechanism, and differentiated functional section design into an anti-buoyancy anchor bolt: (1) By segmented design, the biodegradable bag-buffered dry powder composite layer is strictly limited to the free section, while the anchoring section retains only the anti-corrosion coating and is anchored by conventional cement grouting. This fundamentally avoids the defects of the existing full-length wrapping scheme, which has a severely weakened bonding strength in the anchoring section and is prone to overall slippage. This ensures the reliable pull-out bearing capacity of the anchoring section and achieves anti-corrosion and buffer protection for the free section.

[0018] (2) PGA / PLGA blended fiber woven bags are used. Taking advantage of the fact that both materials are mainly biodegradable, they can achieve controlled degradation without completely relying on microorganisms. By embedding degradation promoters such as calcium oxide in the dry powder, a highly alkaline microenvironment is formed inside the bag. Combined with the alkaline environment of the cement slurry outside the bag, a dual degradation driving mechanism is formed to ensure that the bag can reliably degrade and form a water-permeable channel within a predetermined period.

[0019] (3) The buffer dry powder is innovatively incorporating highly absorbent resin and degradation promoter. When groundwater seeps in, the dry powder becomes wet and forms a non-Newtonian fluid with shear thickening properties. Under earthquake or impact load, it can effectively absorb impact energy and protect the anti-corrosion base coating from damage. The degradation promoter releases alkaline substances after absorbing water, which actively accelerates the hydrolysis of the bag from the inside and achieves controllable degradation.

[0020] (4) The cement content in the dry powder filling inside the bag is only 3% to 6%. Under low water-cement ratio conditions, only slight hydration occurs, which plays a role in stabilizing the particle shape and will not form high-strength blocks, thus ensuring the long-term flexibility of the buffer layer. After the bag degrades, the buffer layer naturally integrates with the surrounding rock and soil, and still maintains its flexible buffering characteristics.

[0021] (5) This invention integrates the construction of anti-corrosion coating, preparation of buffer layer, grouting of anchor section and waterproofing of node into an integrated construction process. The construction steps are clear, the process is closely connected, and it is convenient for on-site operation and quality control. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the anti-buoyancy anchor bolt proposed in this invention. Detailed Implementation

[0023] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto. Example 1

[0024] This embodiment proposes a construction method for integrating anti-buoyancy anchors and waterproof layers, which specifically includes the following steps: S1. Anchor bolt preparation: HRB400 grade hot-rolled ribbed steel bars were selected as the anchor rods, with a diameter of 32mm and a length of 15m. The surface of the rods was sandblasted to Sa2.5 grade for rust removal. Then, a solvent-free epoxy anti-corrosion primer was applied in two coats, with a 3-hour interval between each coat, resulting in a total dry film thickness of 320μm. After coating, the rods were cured for 24 hours.

[0025] S2. Preparation and filling of free segment bags: (1) Preparation of buffer dry powder: Weigh out 1100 kg of river sand (fineness modulus 2.5), 400 kg of fly ash (Grade II), 80 kg of ordinary Portland cement (P.O42.5), 70 kg of sodium bentonite, 25 kg of modified starch, 8 kg of superabsorbent resin (sodium polyacrylate type) and 30 kg of calcium oxide powder per cubic meter of dry powder. Put the above materials into the mixer in sequence and dry mix for 5 minutes until uniform.

[0026] (2) Bag preparation: The bag is a non-woven bag made of PGA fiber and PLGA fiber blended at a mass ratio of 65:35, and the LA:GA molar ratio in PLGA is 75:25. The bag wall thickness is 2.5mm, the inner diameter is 12mm larger than the outer diameter of the anchor rod, the tensile strength is 22MPa, and the elongation at break is 210%. The bag is cut according to the design free section length of 8m, and the length is 8.3m (including the overlap allowance at both ends).

[0027] (3) Filling and sealing: Seal one end of the bag with a heat sealer, and fill the bag with buffer dry powder using a quantitative filling machine. The filling amount is 75% of the bag volume. After filling, vibrate to release the air, and then heat seal the other end.

[0028] S3. Bagging installation: The filled bag is then inserted onto the corresponding free section of the anchor bolt (depth range 2.5–10.5m). Both ends of the bag are secured with stainless steel clamps, with three clamps at each end to ensure a tight fit. The lower part of the anchor bolt (depth 10.5–15m) is the anchoring section; this section is not fitted with a bag, only the S1 anti-corrosion primer is retained.

[0029] Specific anti-buoyancy anchor structure as follows: Figure 1 As shown.

[0030] S4. Drilling and Anchor Installation: An anchor drilling rig was used to drill holes at the designed locations, with a diameter of Φ180mm and a depth of 15.5m, and the verticality deviation was controlled within 0.8%. After drilling, the hole was repeatedly cleaned with high-pressure air. The S3-treated anchor rod was slowly lowered into the borehole, confirming that the free section and the anchoring section were located in the strata corresponding to the designed depths, and temporarily fixed at the borehole opening.

[0031] S5. Grouting of the anchorage section: Cement grout was prepared using P.O42.5 ordinary Portland cement with a water-cement ratio of 0.42, and 0.8% high-efficiency water-reducing agent was added to improve fluidity. The grouting pipe was lowered along with the rod, with the bottom of the pipe 150mm from the bottom of the hole. The grouting pressure was 0.8MPa, and grouting was continuously injected in reverse from the bottom of the hole to the opening until thick grout returned from the opening. After the initial setting of the first grouting, the grout surface settlement was checked, and a second grouting was performed. After curing for 7 days, the compressive strength of the grout reached 34MPa after 28 days.

[0032] S6. Waterproofing treatment of joints: Install a water-stop ring at the connection between the anchor rod and the base plate, fill with water-swellable rubber water-stop strips, and coat the surface with polyurethane sealant. Pour the base plate concrete, vibrate it thoroughly, and complete the integrated construction of the anti-buoyancy anchor rod and the waterproof layer.

[0033] The construction process after completion is as follows: Groundwater slowly seeps into the bag through the micropores and weave gaps, gradually wetting the dry powder inside. The highly absorbent resin absorbs water and swells to form a continuous hydrogel phase. Calcium oxide releases hydroxide ions upon contact with water, creating a highly alkaline microenvironment (pH≈12.5). The moistened powder system forms a non-Newtonian fluid buffer layer with shear-thickening properties, absorbing energy under earthquakes or impact loads and protecting the anti-corrosion base coating. Under the dual effects of the highly alkaline environment inside the bag and the alkaline environment of the cement slurry outside, the ester bonds of PGA and PLGA fibers hydrolyze and break, degrading to form permeable channels, and the buffer layer naturally integrates with the surrounding soil and rock. Example 2

[0034] This embodiment proposes an integrated construction method for anti-buoyancy anchor bolts and waterproof layers. The difference between this embodiment and Embodiment 1 is that: the bag is woven from a blend of PGA fiber and PLGA fiber at a mass ratio of 70:30, and the LA:GA molar ratio in the PLGA is 65:35; the degradation accelerator is calcium hydroxide, with a dosage of 25 kg / m³. 3 . Example 3

[0035] This embodiment proposes an integrated construction method for anti-buoyancy anchor bolts and waterproof layers. The difference between this embodiment and Embodiment 1 is that: the bag is woven from a blend of PGA fiber and PLGA fiber at a mass ratio of 60:40, and the LA:GA molar ratio in the PLGA is 75:25; the cement content in the buffer dry powder is 60 kg / m³. 3 .

[0036] The following comparison model was also set: Comparative Example 1 A sealed anti-corrosion bag is installed along the entire length of the anchor bolt (including the anchoring section and the free section). The bag is not filled with buffer dry powder material, but with ordinary cement grout. After the anchor bolt is lowered as a whole, the anchoring section is grouted, with the grout directly wrapped around the outer surface of the bag. Other construction conditions are consistent with those in Example 1.

[0037] Comparative Example 2 No bags or buffer dry powder were used on the free section of the anchor bolt; only the same anti-corrosion primer (dry film thickness ≥300μm) was applied along its entire length as in Example 1. After the anchor bolt was lowered, grouting was performed directly on the anchoring section. The anti-corrosion coating on the free section was in direct contact with the backfill soil or grout. Other construction conditions remained consistent with Example 1.

[0038] Comparative Example 3 In the preparation of the buffer dry powder, no superabsorbent polymer (SAP) resin was added, and the mass proportions of the remaining components (river sand, fly ash, cement, bentonite, starch, and degradation accelerator) were scaled up to 100% proportionally according to the proportions in Example 1. All other steps, materials, and construction conditions were exactly the same as in Example 1.

[0039] Comparative Example 4 Replace the PGA / PLGA blended fiber woven bag in Example 1 with a regular polyethylene (PE) woven bag with equivalent mechanical properties. PE material is difficult to degrade in the natural environment, and groundwater cannot effectively infiltrate the bag to form a moist buffer. All other steps, material ratios, and construction conditions are exactly the same as in Example 1.

[0040] Comparative Example 5 In the preparation of the buffer dry powder, the mass fraction of cement was increased from 4.5% (approximately 80 kg / m³) in Example 1. 3 The percentage of river sand used was increased to 15%, and the amount of river sand used was reduced accordingly to keep the total mass percentage unchanged. All other steps, materials, and construction conditions were exactly the same as in Example 1.

[0041] Performance testing: Accelerated degradation test: Bag degradation is a pure ester bond base-catalyzed hydrolysis reaction, which is an elementary reaction, and its reaction rate strictly follows the Arrhenius equation: ; k: Hydrolysis reaction rate constant; A: Pre-exponential factor; E a Activation energy for hydrolysis (PGA≈75-85kJ / mol, PLGA≈65-75kJ / mol); R: gas constant (8.314 J / (mol・K)); T: Absolute temperature (K); e: natural constant; The essence of temperature equivalence: Increasing temperature and extending time have equivalent effects on ester bond cleavage. For every 10°C increase in temperature, the hydrolysis rate increases approximately 2-3 times (Q...). 10 ≈2.5); For example, in a highly alkaline cement slurry environment (pH=12.5-13.5), the degradation time conversion formula for the PGA / PLGA (7:3) blended bag of this invention is as follows: ; Underground actual temperature: T1 = 20℃ (293K), target degradation time: t1 = 18 months; laboratory accelerated temperature: T2 = 60℃ (333K), activation energy E a =70kJ / mol; Calculation yields: t2≈28 days, meaning that in the cement slurry immersion test at 60℃ and pH=13, the degradation effect in 28 days is equivalent to the degradation effect in an underground environment at 20℃ for 18 months.

[0042] Table 1. Summary of Performance Test Data

[0043] Data Analysis: 1. Ultimate tensile strength and displacement (Comparison of Example 1 with Comparative Examples 1 and 2): Comparative Example 1: Due to the use of a full-length sleeve, the cement grout cannot directly bond with the anchor rod reinforcement, but instead comes into contact with the smooth outer surface of the sleeve. This artificially creates a weak interface with low bond strength, making the anchor rod extremely prone to overall slippage. As a result, its ultimate bearing capacity drops sharply to 412kN, and the displacement reaches 12.5mm under 1.2 times the design load (far exceeding the standard limit of 5mm).

[0044] Example 1: Strict segmented design was implemented, with the anchoring section completely stripped of the protective bag, allowing the cement grout to directly contact the surface of the steel reinforcement with its anti-corrosion coating. Although the coating reduced the bond strength somewhat, it remained significantly higher than the "bag-grout" interface in Comparative Example 1. Therefore, the load-bearing capacity was maintained at a high level of 685 kN.

[0045] Comparative Example 2: The free section is without a bag, and the anchoring section is exactly the same as in Example 1, so the bearing capacity is basically the same as in Example 1 (690kN).

[0046] 2. Damage rate of anti-corrosion coating after dynamic load (comparison of Example 1 with Comparative Examples 2, 3, 4, and 5): Comparative Example 2 (without buffer layer): The anti-corrosion coating in the free section is in direct contact with the surrounding hard grouting body or soil and rock. Under earthquake or impact dynamic loads, the friction and compressive stress generated by soil deformation directly acts on the brittle coating surface, resulting in large-area cracking and damage to the coating, with a failure rate as high as 15.8%.

[0047] Comparative Example 3 (without SAP): The dry powder lacks highly absorbent resin and cannot form a continuous hydrogel phase. After groundwater infiltration, the lack of flexible gel connections between particles results in a loose sandy texture rather than a non-Newtonian fluid, significantly reducing the buffering and energy absorption effect, and leading to a coating damage rate of 9.2%.

[0048] Comparative Example 4 (PE bags are non-degradable and waterproof): PE woven bags have high mechanical strength but are hydrophobic and non-degradable. Groundwater cannot effectively penetrate into the bag, and the dry powder material remains in a dry and loose state for a long time, failing to form a moist and flexible buffer. Its buffering effect is even worse than that of a moist and compacted sand layer. At the same time, the non-degradable bag body permanently blocks the bonding between the anchor bolt and the stratum, with a damage rate of 12.4%.

[0049] Comparative Example 5 (Excessive Cement Content): When the cement content was increased to 15%, a significant hydration reaction occurred under groundwater infiltration conditions, forming a hard cement-stone body. While this enhanced the strength of the buffer layer, it also caused it to lose its flexibility and deformability. Under dynamic loads, the hard block could not buffer energy dissipation and instead exacerbated local stress concentration on the coating, resulting in a failure rate of 10.5%.

[0050] Example 1 (Optimal Solution): SAP absorbs water to form a hydrogel. The low cement content only serves to stabilize the particles. The PGA / PLGA woven bag allows for slow water seepage before degradation. The system forms a non-Newtonian fluid with shear-thickening properties. Under dynamic loads, the stiffness increases instantaneously to absorb energy, while maintaining flexibility under normal conditions. The coating damage rate is only 2.1%.

[0051] 3. Control of degradation time under bagging (Examples 1, 2, 3): Example 1: PGA fiber and PLGA fiber are blended and woven at a mass ratio of 65:35. The equivalent degradation time is 18 months, which is suitable for the construction period of general engineering projects.

[0052] Example 2: The PGA content was increased to 70%, and the GA molar ratio in PLGA was increased to 35% (the higher the GA content, the faster the hydrolysis). The synergistic effect of the two resulted in the fastest degradation rate, shortening the equivalent degradation time to 14 months.

[0053] Example 3: When the PGA ratio was reduced to 60% and the PLGA molar ratio was maintained at a low GA ratio (75:25), the degradation rate was the slowest, and the equivalent degradation time was extended to 22 months.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for integrating anti-buoyancy anchor bolts and waterproof layers in construction, characterized in that, Includes the following steps: S1. Anchor bolt body preparation: The surface of the anchor bolt body is derusted, and an anti-corrosion primer is applied to the entire length of the anchor bolt body. S2. Preparation and filling of free segment bags: The buffer dry powder is filled into a hydrolyzable and degradable fiber woven bag, and then heat-sealed to obtain a filled bag. The buffer dry powder contains, by weight, 55-65 parts river sand, 18-25 parts fly ash, 3-6 parts cement, 3-5 parts bentonite, 1-2 parts starch, 0.3-0.5 parts superabsorbent resin and 1-3 parts degradation accelerator; The hydrolyzable and degradable fiber woven bag is made of a blend of polyglycolic acid fiber and polylactic acid-glycolic acid copolymer fiber. S3. Bag installation: Insert the filling bag and fix it to the corresponding position of the free section of the anchor rod; The free section is the section of the anchor rod body that does not require anchoring force, while the anchoring section of the anchor rod body that requires pull-out resistance is not fitted with a sleeve. S4. Drilling and Anchor Installation: Drill holes at predetermined locations, clean the holes, and then place the treated anchor rods into the drilled holes. S5. Anchorage section grouting: Inject cement grout into the anchorage section and cure it after grouting is completed; S6. Waterproofing treatment at joints: A waterproof structure is installed at the connection joint between the anchor rod and the base plate, and the base plate concrete is poured.

2. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, In S2, the mass ratio of polyglycolic acid fiber to polylactic acid-glycolic acid copolymer fiber in the hydrolytically degradable fiber woven bag is 60-70:30-40. In polylactic acid-glycolic acid copolymer fibers, the molar ratio of lactic acid units to glycolic acid units is 65-75:25-35.

3. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, In S2, the degradation promoter is calcium oxide or calcium hydroxide; The superabsorbent resin is added at 0.2% to 0.5% of the cement mass, in a dry manner; the filling amount of the buffer dry powder is 70% to 80% of the bag volume.

4. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, In S1, the anti-corrosion primer is an epoxy anti-corrosion primer or a polyurea anti-corrosion primer, and its dry film thickness is not less than 300μm.

5. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, In S2, the hydrolyzable and degradable fiber woven bag is a woven bag or a non-woven bag, with a tensile strength of not less than 20 MPa and an elongation at break of not less than 200%.

6. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, In S2, the buffer dry powder should be used up within 24 hours after preparation, and the filling bag should be kept dry and sealed before installation.

7. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, In S3, both ends of the bag are fixed to the anchor rod body by corrosion-resistant cable ties or stainless steel clamps, and at least two fixing parts are provided at each end.

8. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, In S5, the water-cement ratio of the cement grout is 0.40 to 0.45, the grouting pressure is 0.5 to 1.0 MPa, and the 28-day compressive strength of the grout body is not less than 30 MPa.

9. The integrated construction method of anti-buoyancy anchor and waterproof layer according to claim 1, characterized in that, After the S5 grouting is completed, the dry powder material inside the free section bag is moistened by groundwater infiltration, forming a non-Newtonian fluid buffer layer with shear thickening properties. Under the alkaline environment created by the degradation accelerator inside the bag and the cement slurry outside the bag, the bag gradually hydrolyzes and degrades within 12 to 24 months, forming water-permeable channels.

Images