Load-Settlement Characteristics of Drilled Shafts Reinforced by Rockbolts

This paper describes the load distribution and settlement of reinforced drilled shafts subjected to axial loads. The emphasis was on quantifying the reinforcing effects of rockbolts placed from the shafts to surrounding weathered rock based on a numerical analysis and 1/8 scale load tests performed on instrumented piles. The piles with and without rockbolts were instrumented with strain gages, load cell and tell tale, and load tests were performed on four piles: tension and compression. The results of the four load tests are presented in terms of top load-top movement curves. In addition numerical analyses are performed for the major influencing parameters on the behavior of reinforced drilled shafts such as the number of rockbolts, the positions on the shaft, reinforcement level, and the inclination angle at which the rockbolts are placed. As a result, the parametric study is highlighted. It was found that as the number of reinforcing levels increases, the incremental effect of reinforcement tends to increase, whereas the reinforcing effect on relative positions is negligible. In addition there is a reinforcing effect as the inclination angle increases up to 30 degrees.