Download 
The Application of Self Drilling Anchor Bolt at the Tala Hydro Project for Tunneling in Poor Rock Mass Conditions
Time:2015-08-20Viet: 0
The Tala hydroelectric project is located in Chukha Dzongkhag in western Bhutan. The dam site is in the Thimphu gneiss, and the section of HRT up to 14km downstream from C-1 is in gneiss with quartzite bands and biotite schists. There are joint sets, and the rock is highly faulted, with foliation shears of varying thickness up to 30cm. From 14km to 23km, the rock type is biotite gneiss with bands of quartzite, mica schist, and sericite schist with amphibolite. Rock conditions merit 3 - 4 on the NGI Q system, with pretty poor conditions affecting parts of C2, C-3 and all of C-4. The rock formation in the power house and penstocks, envisaged to be in classification 2 - 3, showed a large variance during actual excavation.Self drilling anchor bolts were in widespread use at Tala for stabilization of the desilting chamber walls and for tunneling in poor rock mass conditions. They are reinforcement tools which, unlike other types of rockbolts, are equipped with a drillbit of their own which allows them to be installed in one operation in rock, highly fractured weak formations, and even soil where the drill hole collapses and conventional anchor systems cannot be installed.
Self drilling anchor bolts have been successfully used for stabilizing the RCC wall of desilting Chamber No.3, behind which enormous cracks had been observed by borehole camera investigation. The strata encountered was so fragmented that the drilled holes would not stay open long enough to install longer rock bolts. The wall of the chamber has been anchored to the deeper competent rock using one row of 114 anchors with 20m length and 38mm diameter at 3m centers, and another row of 36 anchors with 24m length and 51mm diameter at 3m centers.Mining is the extraction
- Pre: Back To List
- Next: Back To List
latest cases
-
- The Slope Support Project of Dong Miao Residential Area in Ji Nan
- Time:2015-10-30From:This Site
- The traditional deep excavation retaining method can not meet the requirement of the stabilization of large-scale underground buildings. Especially in sandy cobble stratum where the ratio of finishing gas hole is very low, it must lead to high pressure for the grouting and anchoring later and increase the construction cost.
- View details
-
- The Construction Method of Self Drilling Anchor Bolt in Sandy Gravel Deep Excavation
- Time:2015-10-22From:This Site
- With the exploitation of the underground space in cities and the large scale construction of the underground retail spaces, the deep excavation projects is becoming more and more.
- View details
-
- The Application of Self Drilling Anchor Bolt in Beijing Oriental Plaza Foundation Support Project
- Time:2015-08-20From:This Site
- In recent years, the self drilling anchor bolt plays a more and more important role in the foundation support projects. The unconsolidated ground condition favors it for fast and simple method of installation compared to the traditional method. It has many good features just as follows:
- View details
-
- Application of Self-drilling Anchor Bolts in Vertical Shaft at Left Bank of Xiluodu Hydropower Station
- Time:2015-08-20From:This Site
- Self drilling anchor bolt has two performances: drilling and grouting. It features a hollow bore for flushing, or simultaneous drilling and grouting. It can be installed in sites with weak rocks, loose soil, weathered layer, sand with stone layer where it is so difficult to create a hole in complex formation. The unconsolidated ground conditions favor the self drilling anchor bolt technique for fast and simple method of installed compared to the traditional method, which was confirmed by the application in Vertical Shaft at Left Bank of Xiluodu Hydropower Station.
- View details
-
- The Application of Self Drilling Anchor Bolt at the Tala Hydro Project for Tunneling in Poor Rock Mass Conditions
- Time:2015-08-20From:This Site
- The Tala hydroelectric project is located in Chukha Dzongkhag in western Bhutan. The dam site is in the Thimphu gneiss, and the section of HRT up to 14km downstream from C-1 is in gneiss with quartzite bands and biotite schists. There are joint sets, and the rock is highly faulted, with foliation shears of varying thickness up to 30cm. From 14km to 23km, the rock type is biotite gneiss with bands of quartzite, mica schist, and sericite schist with amphibolite. Rock conditions merit 3 - 4 on the NGI Q system, with pretty poor conditions affecting parts of C2, C-3 and all of C-4. The rock format
- View details
