Minimum Required Length for Geotechnical Lateral Stability of Rock-Socketed Pile Shafts

The original strong-rock (SR) p-y curves for rock-socketed shafts exhibit a brittle response where the post-peak resistance drops to approximately zero. This brittle response could result in a progressive failure of the rock p-y curves which, in turn, results in excessive pile lengths. This paper proposes a modification to the strong-rock (SR) p-y curves where the post-peak residual strength is equal to 20% of the ultimate resistance (0.2*p_ult). This residual resistance is proposed based on the assumption that the lateral resistance of cracked rock (after the peak point) should not be smaller than the lateral resistance of heavily weathered rock estimated from the weak-rock (WR) and Liang et al. p-y curves. The effectiveness of the modified SR curves is evaluated against the results of a lateral load test. The modified SR curves are compared against back-calculated p-y curves from the lateral load test.