The construction method for slope protection net.

As a standardized structure, the installation of active slope protection nets is crucial to ensure their effectiveness. The correct structure and connection methods must be followed, or the protective capability cannot be guaranteed. Similarly, if the system's shape is altered due to rockfall impact, its protective ability may be reduced to varying degrees.

 

As a standardized structure, the installation of active slope protection nets is crucial to ensure their effectiveness. The correct structure and connection methods must be followed, or the protective capability cannot be guaranteed. Similarly, if the system's shape is altered due to rockfall impact, its protective ability may be reduced to varying degrees. To maintain its long-term protection, proper maintenance is essential. Since detailed methods are usually provided in the design specifications or product installation manuals, this section will focus only on general principles, key procedures, and precautions.

 

1. Slope Cleaning

In most cases, slope cleaning is not necessary, but it should be considered under the following two conditions:

a. When there are loose soil or rocks, especially in the area where workers are operating, that could cause collapses or rolling debris due to construction activities and pose a safety threat, it is advisable to remove them or provide temporary on-site treatment.

b. For any isolated, dangerously loose rocks on the slope that have a high likelihood of collapsing in the future, and if their collapse could require substantial maintenance or exceed the system’s protective capacity, it is recommended to either reinforce them or remove them in advance.

 

 

2. Marking and Layout

Although the anchor positions in the standardized structure have specific size constraints, there is some allowance for adjustment, especially for anchors, which have greater flexibility in positioning. Additionally, the actual site conditions are often complex and may not be fully reflected in the design drawings, particularly with regard to features that can be utilized or require special attention.

Marking involves determining the anchor hole positions through measurements (the spacing between holes can be adjusted by up to 0.3m based on terrain conditions). At each anchor hole position, a pit should be chiseled to a depth no less than the length of the exposed anchor loop, typically with a diameter of 20 cm and a depth of 15 cm.

 

3. Foundation Construction

This work is primarily aimed at ensuring the anchoring capability of the anchors. For locations on bedrock or hard soil, it specifically involves drilling anchor holes, while for loose soil where direct hole formation is not possible, it may include excavation and concrete foundation pouring.

Anchor holes should be drilled to the design depth and cleaned, with the hole depth exceeding the designed anchor length by at least 5 cm and the diameter not less than φ42. If drilling equipment is limited, two strands of steel rope forming each anchor can be anchored into two holes with a diameter of at least φ35, creating a V-shaped anchor configuration. The angle between the two steel ropes should be between 15° and 30° to achieve the same anchoring effect.

 

 

4. Anchor Installation

For anchor positions where holes are directly formed, the anchors are installed using a grouting method. In locations with concrete foundations, anchors are generally embedded directly while pouring the foundation concrete.

During grouting, the anchors should be inserted (the top of the exposed anchor ring should not exceed the ground surface, and the ring section should not be grouted to ensure that the support rope is as close to the surface as possible after tensioning). The grout should be no less than M20 cement mortar, ensuring that the grout fills the hole completely. The grouted area should be cured for no less than three days before proceeding to the next step.

 

5. Support Rope Installation and Adjustment

Install the longitudinal and transverse support ropes, and after tensioning, fix each end to the exposed anchor ring with 2 to 4 wire clamps (2 clamps if the support rope length is less than 15m, 3 clamps for lengths between 15m and 30m, and 4 clamps if longer than 30m).

Hang the grid mesh from top to bottom, ensuring that the overlapping width between grids is no less than 5cm. Sew the seams between the two grids and tie the grid mesh to the support ropes using φ1.2 iron wire at 1m intervals (if conditions allow, this step can be completed before the previous one, placing the grid mesh under the support ropes).

 

6. Grid Mesh Installation

Hang the grid mesh from top to bottom, ensuring that the overlapping width between grids is no less than 5cm. Sew the seams between the two grids and tie the grid mesh to the support ropes using φ1.2 iron wire at 1m intervals (if conditions allow, this step can be completed before the previous one, placing the grid mesh under the support ropes).

 

 

7. Steel Rope Mesh Installation and Sewing

Install the steel rope mesh from top to bottom, sewing it together using φ8 steel rope. Each steel mesh is sewn to the surrounding support ropes with a stitching rope approximately 31m (or 27m) long, and pre-tensioned. The ends of the stitching rope are secured to the mesh ropes using two rope clamps.

 

8. Finalization Process

Once the system installation is complete, if conditions allow, it is advisable to use soil or small stones to weigh down the laid-out mesh on the ground. This helps prevent falling rocks from lifting the mesh upward.