Foundation Support

The Application of the Self Drilling Anchor Bolt in the Foundation Support of CSIC Mansion

Date: 2015-05-16view:

 The project is located in the north of Haier Road, Qingdao and Tongan Road intersection. Due to the large height difference, the excavation depth was between 7.5 ~ 15.0m after leveling. The length of the foundation is about 254m, and width 80m. In this paper, the excavation depth of the MD unit mentioned is 12m, which is back-filled from a pond. The stratum is as follows:

1. Miscellaneous Fill: Construction waste and gravel-based;silty soil included; an average thickness of 18m

2. weathered granite: hard plastic, wet, in-tight; mechanical properties gradually increasing from the top down

3. Groundwater: more underground seepage due to abundant water pit from underground fissures

Self-drilling anchor bolt has two performance: drilling and grouting. It features a hollow bore for flushing, or simultaneous drilling and grouting. It is a reliable and convenient anchoring system which is applied in complicated geological conditions for rock support work. It is widely used in tunneling, mine, slope stabilization and foundation support. The unconsolidated ground condition favor the self drilling anchor bolt technique for fast and simple method of installed compared to the traditional method.

MD unit adopts the R32 self drilling anchor bolt. The thickness of the spraying surface coat is 100mm. The grouting pressure is 0.5~2Mpa and the water-cement ratio is 0.45~0.050. The intensity of grouting can not be less than M20. The length and interval of the self drilling anchor bolts are as follows:      

Each Level




Drilled Hole
Lean Angles(°)

1  10 1.5 1.0 15
2 12 1.5 1.5 15
3 13 1.5 1.5 15
4 12 1.5 1.5 15
5 12 1.5 1.5 15
6 10 1.5 1.5 15
7 9 1.5 1.5 15
8 7 1.5 1.5 15

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