In the construction of slope protection, why must be self drilling hollow anchor bolt? There are some reasons in below:
1. Integration of drilling, grouting and anchoring as a whole. Self drilling hollow anchor bolt can ensure the anchoring effect in complex ground conditions. It has the features of safety, reliability and efficiency.
2. Rapidly initial support, control the deformation and ensure the stability of surrounding rock.
3. The hollow design makes the anchor bar achieve the function of a grouting pipe, thus avoiding the loss of mortar caused by the grouting pipe in the traditional construction process.
4. The grouting is full. The pressure grouting can be realized to improve the quality of the project.
5. Due to the role of the accessories, the hollow bar can be well placed in the middle. The mortar can cover the hollow bar in full length, avoid the risk of corrosion, and achieve the purpose of long-term support.
6. Easy installation. It’s easy to place the plate and nut without processing thread on site.
7. Combined with the matched grouting pump and grouting technology, at present, self drilling hollow anchor bolt is the only anchoring system to solve the problems of traditional anchoring support in China.
Friendship Tunnel is a cross-border tunnel connecting China and Laos, with a the total length of 9.68 km, 7.17 long in China and 2.51 km long Laos, planned to spend 56 months. The name of Friendship Tunnel means the deep friendship between the two countries. On June 22, 2016, Friendship Tunnel officially started construction, which marked that the midline of Trans-Asian Railway Network started to enter a substantive stage. The project leader of China Railway Erju Group (CREGC) said Friendship Tunnel has poor engineering geological conditions and high risk of construction because of siltstone interbedded with mudstone. To ensure the safety and efficiency of tunnel construction, CREGC is in strict accordance with the design parameters of support. Friendship Tunnel would greatly push forward the“One Belt And One Road”.
Tips: Metis® self drilling hollow anchor bolt can be used as stabilization of tunnel portals, fore-poling, face stabilization, spilling, root piling and radial systematic anchoring， which is the choice of most engineers for tunnel engineering construction.
In water conservancy projects and various underground works，there are generally complicated geological conditions such as soft and weak surrounding rocks and fault fracture zones. Especially in case of serious hole collapse and need of extreme long rock bolts，the construction of ordinary mortar rock bolts is very difficult.
Based on the construction of slope excavation support of the diversion channel for Banduo hydropower project, self drilling hollow anchor bolt instead of ordinary mortar anchor bolts in case of broken rocks and clay rocks can overcome the problems such as slow construction progress, impossible insertion of bolts, hole collapse, and ensure the overall stability of surrounding rocks. Under the lithology, the geological conditions is mainly thin sand slate sandstone and the width of broken belt is general 5 ~ 20 cm. This project uses neat cement grout to grout, water-cement ratio of 0.45 /0.5: 1, and the pressure of injection pump infusion is less than 0.3 MPa.