Seismic Performance of Deposit Slopes with Underlying Bedrock before and after Reinforcement by Stabilizing Piles

The seismic performance of stabilizing piles used to reinforce underlying bedrock in a deposit slope is a complex soil–structure interaction problem. Two centrifuge shaking table model testswere conducted to ascertain the dynamic responses of the underlying bedrock deposit slopes without and with the use of stabilizing piles during an earthquake. Multi-stage seismic waves with various peak accelerations were applied from the bottom of each model. The differencesin the response accelerations between the deposit and bedrock increase significantly with the increase in amplitude of the input seismic waves. The presence of the rock-socketed stabilizing piles can bridge the uncoordinated movement of the bedrock and the overlying deposit to some extent. The resultant force arising from a distributed load increment on the piles caused by an earthquake is mainly concentrated in the upper part. With increases in the peak ground acceleration of the input motion, the resistance of the bedrock in front of the stabilizing piles increases and the peak resistance under the bedrock surface of the stabilizing piles gradually moves downwards.This finding indicates that the strong seismic motion significantly changes the embedded working state of the stabilizing pile.

A Robust and Efficient Method of Designing Piles for Landslide Stabilization

ABSTRACT Stabilizing pile is a widely used method to reduce the development of large-scale landslides. Optimizing the pile geometry is a great challenge in the design of stabilizing piles with the purpose of cost-effectiveness, especially for soil strength parameters with large uncertainty. The objective of this study is to propose a robust and efficient method of designing piles for landslide stabilization with the consideration of the safety of slope, uncertainty of soil parameters, and cost of stabilizing piles. A new response surface, which incorporates soil parameters and stabilizing force into a quadratic polynomial function, is first proposed. Unknown coefficients of the quadratic polynomial function are solved with a numerical method at typical sampling points. Based on the solved quadratic polynomial function, the mean and standard deviation of factor of safety (FOS) of the pile-stabilized slope as well as the signal-to-noise factor are then calculated in order to evaluate the design robustness. A framework based on the concept of robust geotechnical design is presented, and its feasibility is illustrated by two cases of soil slopes. The results indicate that the proposed robust geotechnical design method could be used to optimize the design of landslide-stabilizing piles.

Effect of the Soft and Hard Interbedded Layers of Bedrock on the Mechanical Characteristics of Stabilizing Piles

In this paper, the mechanical characteristics of stabilizing piles embedded in layered bedrocks are studied both experimentally and numerically. The influence of soft and hard interbedded layers in the structure of the bedrock on the mechanical characteristics of stabilizing piles is particularly investigated. The discrete element method is used to numerically investigate the response of the stabilizing piles embedded in composite and inclined bedrocks. The simulation results and comparison with experimental data are presented to demonstrate the effectiveness and accuracy of the discrete element model. As the dip angle of the soft/hard interbedded bedrock layers increases from 0° to 45°, it is observed that the displacement of the embedded section of the stabilizing pile increases and reaches the maximum displacement at 45°. In the range of 45° to 75°, the influence of the dip angle of the layered bedrock on the displacement of the embedded section of the pile is gradually reduced.