SNS Flexible Protective Mesh System Construction Methods and Technical Measures

1. Remove Slope Loose Stones

Initially, two φ48 steel pipes, at least 2 meters deep, were driven side by side into the solid soil layer at the slope's crest, with about 1 meter exposed; then, the exposed pipe sections were tied to nearby large trees using ropes with a diameter of no less than 1 cm. Finally, construction workers wore full safety gear, including hard hats and safety belts, with the belt's other end securely fastened to the exposed steel pipes. They utilized hoisting ropes to clear loose stones and soil from above.

2. Survey and Staking

The alignment survey determines the anchor bolt hole positions, with deviations less than 0.3 meters. Aim to select anchor bolt holes in the lowest凹 areas: For locations that are not low or do not meet the requirement of being tightly adjacent to the slope after system installation, a depression of at least the length of the exposed anchor bolt collar should be carved at the hole position, typically measuring 20×20 cm.

3. Anchor Rod Construction

1) The anchoring holes are located by surveying and laying out (with an adjustable spacing of 0.3m based on terrain conditions), then drilled to the design depth. The holes are cleaned, with a depth exceeding the design anchor length by at least 5cm, and a diameter of not less than φ42. When drilling equipment limits are encountered, the two strands of steel rope that make up each anchor can be separately anchored into two holes with a diameter of not less than φ35, forming an X-shaped anchor. The angle between the two strands is 15° to 30° to achieve the same anchoring effect.

2) Grouting and insertion of anchor rods (the exposed loop sleeve of the anchor rod cannot exceed the ground surface, and the grouting of the loop section is not allowed, with the *** supporting rope tensioned as tightly as possible against the ground surface), using cement slurry with a grade not lower than M20, pure cement slurry with a water-cement ratio of 0.45 to 0.50, ensuring the grout is full. Before proceeding to the next step, the grouting body must be cured for at least three days.

4. Install vertical support ropes

Firstly, install longitudinal φ12 support ropes along the entire slope. Secure the rope ends at the slope's top with three rope clips, and then sequentially pass the support ropes through the steel rope anchor bolts' rings at the same vertical line positions across the slope.

5. Install cross-support ropes

A horizontal φ16 support rope is installed along the entire slope from top to bottom. First, one end of the rope is locked onto the steel rope anchor rod sleeve with three rope clips, then the horizontal support rope is sequentially passed through the same level steel rope anchor rod sleeves from left to right or right to left.

6. Tensioning and locking of longitudinal and transverse support ropes

After the entire slope wire mesh supported by transverse and longitudinal ropes is woven, the longitudinal support ropes are first tensioned from left to right or right to left using a small electric winch. After each rope is tensioned, it is locked with a rope clip. Once the longitudinal support ropes are tensioned, the same method is used to tension the transverse support ropes from top to bottom, one by one. After the support ropes are tensioned tightly, two to four rope clips (two when the rope length is less than 15m, four when greater than 30m, and three otherwise) are used to connect and secure each end with the exposed collar ring of the anchor bolt.