To ensure the construction quality of anti-floating anchor rods, several aspects can be addressed:

**Phase I: Pre-construction Preparation**

Geological Survey

- Conduct thorough geological surveys to accurately understand the geological conditions on the construction site, including soil layer distribution, groundwater levels, and rock characteristics. This is the foundation for designing rational anti-floating anchor rods, as different geological conditions have a direct impact on the design parameters of anti-floating anchor rods (such as anchor rod length, diameter, and spacing).

- For instance, in soft soil layers, anchor rods may require longer lengths and larger diameters to ensure adequate anchoring force; in rock layers, the length of the anchor rods can be relatively shorter, but the integrity of the rock and the development of joints must be considered.

2. **Design Plan Review

Thoroughly review the design plans for anti-float anchor rods to ensure they comply with relevant regulations and standards, and meet the actual engineering requirements.

- Verify the rationality of design parameters, such as the arrangement of anchor rods (spacing, row distance), anchor length, and the strength of anchor rod materials. At the same time, pay attention to whether the design plan clearly specifies the requirements for construction methods and quality control.

- For instance, the design plan should clearly specify the key parameters such as the bore diameter of anchor rods, the mixing ratio of grouting materials, and the tension locking force of the anchor rods.

Material Inspection

- Rigorous quality inspections are conducted on the materials entering the site, such as steel bars, steel wires, cement, sand, etc.

- The mechanical properties of rebars and steel strands, such as yield strength, tensile strength, and elongation, should meet design requirements and relevant standards. The cement should be inspected for its strength grade and stability, and the fineness modulus and silt content of the sand should also comply with the specifications.

For instance, the ratio of the measured tensile strength to the measured yield strength of the rebar should not be less than 1.25, and the ratio of the measured yield strength to the standard strength should not exceed 1.3.

4. **Construction Equipment Commissioning**

- The drilling equipment, grouting equipment, and tensioning equipment were adjusted and inspected to ensure their optimal performance and normal operation.

- The drill bit diameter of the drilling equipment should meet the design requirements, the pressure and flow of the grouting equipment should be able to satisfy the needs of the grouting process, and the accuracy and range of the tensioning equipment should comply with the requirements of anchor bolt tensioning.

- For instance, the grouting pressure of the grouting equipment should be adjustable within a certain range to accommodate the grouting requirements under different stratigraphic conditions.

**II. Construction Process Phase**

Drilling Quality Control

- Rigorously control the drilling location, hole diameter, depth, and perpendicularity.

- The deviation of the drilling location should be within the allowable range specified in the design, generally not exceeding 50mm. The hole diameter should meet the design requirements, with the deviation not to exceed 10mm. The hole depth should be deeper than the design depth by more than 0.5m to ensure the anchoring length of the anchor rod.

- We utilize appropriate drilling techniques and equipment, such as using mud-cased drilling in sandy soil layers and hammer drilling in rock formations. Additionally, we regularly employ equipment like inclinometers to monitor the verticality of the boreholes, adjusting any deviations promptly.

- For instance, during the drilling process, measure the verticality of the bore hole at regular depths (such as every 5 meters) to ensure that the deviation remains within the permissible range.

2. **Quality Control of Hole Cleaning**

- After drilling is completed, a thorough cleaning of the borehole is mandatory, ensuring all debris such as rock fragments and soil are completely cleared.

- The cleaning method can be air blowing, high-pressure water flushing, or a combination of both. After cleaning, the thickness of the sediment at the bottom of the hole should meet the design requirements, generally not exceeding 50mm.

For those using high-pressure water flushing to clean holes, it is essential to control the pressure and water volume to prevent damage to the hole walls.

3. **Quality Control in Anchor Rod Manufacturing and Installation**

- Anchor rods should be manufactured strictly according to design specifications, with the length, diameter, and connection methods of steel bars or steel wires conforming to standards.

- The installation of anchor rods should ensure they are centrally positioned within the hole, avoiding contact with the hole wall. For those using rebar anchor rods, the quality of the welding should meet the requirements, with the welding length and weld fullness to be inspected.

- For instance, the welding joint of steel rebar anchor rods should be double-sided焊接, with a welding length not less than 5d (where d is the diameter of the steel rebar).

4. **Grouting Quality Control**

- The mixing ratio of the grouting materials should be strictly prepared according to the design specifications, with precise control of the water-cement ratio in cement slurry and the sand-cement ratio in cement mortar.

During the grouting process, it is essential to control the grouting pressure and volume to ensure that the grout completely fills the borehole and forms a good bond with the surrounding strata.

- Utilize appropriate grouting techniques, such as single-grouting and double-grouting, etc. For double-grouting, it is essential to reasonably control the time interval and pressure between the two groutings.

- For instance, grouting pressure is generally determined based on stratigraphic conditions and design requirements, typically ranging between 0.5 and 2.0 MPa. During the grouting process, monitor changes in grouting pressure and the consumption of grouting material. Stop grouting when the grouting amount reaches the design specification or the grouting pressure stabilizes.

5. **Anchor Rod Tensioning and Locking Quality Control**

- Anchor bolt tensioning and locking can only be performed after the grouting body has reached the required design strength.

- Tensioning equipment should be calibrated, and the tensioning process should be operated strictly according to the specified tensioning sequence and tension force as required by the design.

- When locking, the anchor plate should tightly fit the anchor rod, and the locking force should meet the design requirements. At the same time, attention should be paid to observe the deformation of the anchor rod during tensioning and locking to prevent any anomalies.

- For example, the calibration cycle for tensioning equipment typically lasts for six months or after 300 uses, whichever comes first. During the tensioning process, record the elongation of anchor rods at each tensioning level. If the elongation exceeds the allowable design value, the tensioning should be paused, the cause should be investigated, and appropriate measures should be taken.

**Phase Three: Construction Acceptance Stage**

Quality Inspection

- Conduct quality inspections on floating anchor rods, including reviews of raw material inspection reports, construction records, and concealed work acceptance records.

- On-site pullout tests were conducted to verify whether the anchor bolt's anchoring force meets the design requirements. The number of pullout tests should comply with relevant specifications and design requirements, generally not less than 3% of the total number of anchor bolts, and at least 3 anchor bolts.

- For example, the tensile test should be conducted using a stepped loading method, with each step representing 10% - 20% of the design tensile force. Stop loading when the anchor rod shows a sharp increase in displacement or reaches the failure load.

2. **Acceptance Criteria:**

The acceptance of anti-float anchor rods should comply with relevant national and local standards, such as the "Construction Quality Acceptance Standard for Foundation Engineering of Buildings" (GB 50202), etc.

- Technical specifications of anchor rods, such as length, diameter, spacing, anchoring force, and grouting quality, should meet design requirements and acceptance standards.

- For instance, the length deviation of anchor rods should not exceed ±50mm of the designed length, the diameter deviation should not exceed ±5mm, and the anchoring force should be no less than 90% of the designed value.

3. **Issue Resolution**

- If issues are identified during the quality inspection and acceptance process, they should be analyzed and addressed promptly.

- For issues such as insufficient anchoring force of anchor rods and inadequate grouting density, measures such as adding anchor rods and conducting secondary grouting can be taken to address them. After the treatment, the quality should be re-inspected until it meets the required standards.

- For instance, if the anchor bolt's anchoring force is found to be insufficient during the tensile test, additional anchor bolts can be installed nearby or the original anchor bolt can be subjected to a secondary high-pressure grouting to enhance its anchoring force. Following this, a further tensile test should be conducted to confirm that it meets the required standards.