The Relationship between Field Measurements and Soil Behavior inTNEC Deep Excavation

Abstract

In urban deep excavations, instruments are placed to monitor deformations and to control construction and reduce the risk of excessive and potentially damaging deformations. Data collected from these instruments are also used in inverse analyses to develop improved soil models suitable for representing soil response during excavation. The second author has introduced a new inverse analysis approach, SelfSim, that utilizes measured excavation performance to extract the underlying soil behavior. A systematic study with synthetically generated set of instrument measurements using an idealized soil profile shows that in addition to the measurements of lateral wall deflections and surface settlement, inclinometers further away from the wall are equally important in extracting soil behavior. In this paper a deep excavation case history is studied to implement the findings of the numerical study. The 18-story Taipei National Enterprise Center (TNEC) building with five basement levels was constructed in 1991. The measured lateral deformations of inclinometers in the wall and 22-m further away from the wall are used to extract the constitutive model through the inverse analyses approach. The extracted constitutive model is used in predicting the other inclinometer measurements located at different distances from the wall and surface settlements behind the wall. The predicted behavior of the excavation and its agreement with measurements at the site are discussed in detail.