The soil deformation during diaphragm walls trenching process cannot be avoided. However, it could noticeably vary from project and another due to many factors. Such deformation in the soil will also affect the nearby deep foundation. In this research the numerical analysis using FLAC 3D was adopted to focus on the effect of soil deformation due to trenching on nearby piles. This numerical method was verified by simulating one case history in Hong-Kong and a centrifuge model test which was conducted in Cambridge. The results from the numerical analysis were quite in a good contrast with the field data and laboratory results. The verified numerical analysis method was used to conduct a numerical parametric study that can understand the effect of a single panel on the nearby deep foundation consists of single pile group. The parameters used in the parametric study were the panel dimension, slurry and groundwater level. The deflection and bending moment of the first pile within the group is the main output from the parametric study. The panel length has the greatest effect than its thickness and depth. The effect of slurry level is great if it is lower than the guide wall bottom level. As a general finding the decrease of the panel length and controlling the slurry level will reduce the influence of trenching process on surrounding ground and hence nearby piled foundation.