Stress monitoring model for foundation pile based on variable separation of wavelet

Stress of foundation pile is more sensitive than the other monitoring indexes such as displacement, so it can be observed to show run behavior more efficaciously. Stress components must be separated by influence factors, and stress monitoring model can be built by the relationship of stress components and their influence factors. Wavelet shows good characteristics in time-frequency domain, so it has evident superiority for data analysis and effect component separation under complicated engineering condition. Taken the inner stress of foundation pile in main tower pier pile group of Sutong Bridge as an example, a new method to build stress monitoring model is introduced. Firstly the placement of stress observation points is given. Based on wavelet multi-resolution analysis, the process of component separation and monitoring modeling is given. By analysis of influence factors of stress under complicated engineering condition and selection of right wavelet, stress components, which influenced by temperature, tidal level and load and so on, can be separated from observed stress series. So, stress monitoring model of foundation pile is built by summed all stress component. It is certified that the model shows stress situation of foundation pile and the relationship with influence factors effectively.