Abstract：
For controlling large deformation of soft rock tunnels, a support scheme with lengthened rock blots is presented after an analysis of large deformation causes was performed using the Siping tunnel on the Gucheng-Zhuxi highway as an example. In the past, the length of systematic anchor bolts was determined empirically and lacked reasonability. So an in-situ wave velocity test and theoretical calculations were used to determine the proper length of rock bolts, and finally it was determined that the rock bolts should be 5m in length based upon the effects of safety and economy. Based on the in-situ monitoring and measurement, along with a site test, a comparison test was adopted for the new support option featuring lengthened rock bolts and the original heavy-support option. The results show that the lengthened rock bolts can control deformation more effectively and take advantage of rock masses with self-stability and the ability for self-support in light of rock deformation, force, and the force pattern of the support structure.
SUN Yang,
Zuo-Chang-Qun,
Liu-Miao etc
.Application of Lengthened Rock Bolts for Large Deformation Control
in a Soft Rock Tunnel
[J] MODERN TUNNELLING TECHNOLOGY, 2014,V51(3): 174-180
2014, Vol. 51 