Risk analysis of pile pressing-in on an adjacent earth-retaining wall

Pile pressing-in is a green pile installation technology that uses hydraulic jacks to press piles into the ground. It is environmentally friendly as it eliminates the noise and vibration nuisance as well as air pollution problems. The current state of development of the pressing-in technique and equipment allows piles to be pressed-in very close to existing permanent or temporary earth-retaining walls. The piles being installed may induce additional lateral loads on the retaining wall and/or excessive movement of the wall, and may thus have detrimental effects on the stability of the wall. It is of great importance to understand these adverse effects that may be induced by pile pressing-in to ensure the stability of any nearby retaining walls. However, it is extremely expensive and time-consuming to conduct a full-scale evaluation. Therefore, laboratory evaluation using a scaled model was adopted in this research. The availability of a hi-tech tactile pressure sensor mat makes it possible to measure the normal stress on a laboratory-scale model retaining wall with high accuracy. Based on a series of laboratory tests, the variation of factor of safety against sliding k with distance between the pile and the retaining wall was quantified. Influences of the movement of the retaining wall on k were studied. Limitations of the current research are also discussed.