Prediction of lateral capacity losses of a single pile adjacent to excavation of foundation pits based on CPT tests

The prediction of lateral capacity losses of a single pile adjacent to the excavation of foundation pits is made, by designing the excavation of a test pit in multi-layer soils based on CPT tests. The CPT-qc curves before and after the excavation of the test pit are obtained and compared, and the lateral capacity losses of the single pile adjacent to the excavation of the test pit and its bending moment characteristics are analyzed using CPT-based p-y curve models. The residual lateral capacity of the test pile after exaction unloading and the lateral bearing rules facing the combined loadings from horizontal forces on pile head and soil movement forces are evaluated. The results show that using the actual CPT parameters of unloading soils is more reasonable than that of free-ground soils for the prediction of lateral capacity losses of a single pile adjacent to the excavation of foundation pits. The lateral capacity reduction after adjacent excavation unloading and the influences of lateral soil movement on piles must be taken into account in the design of engineering pile foundations. The study about CPT tests on unloading soils gives a technical approach for estimating the lateral capacity losses of the single pile adjacent to the excavation of foundation pits and has referential meanings for the evaluation of excavation unloading piles. © 2019, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.