Effect of constitutive models in prediction of displacement fields and structural forces of the support system elements used in urban excavations

Design and execution of excavations in urban areas requires having sufficient knowledge of the environmental effects of these structures. Given the importance of this matter, numerical methods may not be used solely as a research tool. However, these methods may be used for designing and executing these structures. The type of constitutive model and input data play an important role in the response and quality of modeling. Mohr-Coulumb is the most common constitutive model in numerical modeling with some weaknesses such as unrealistic heave of the excavation bottom and thus variations in the displacement field. In this paper, a simulation of an excavation and support system by using a combined method of nailing and anchorage was carried out with two constitutive models, Mohr-Coulumb and hardening soil models. Analysis results showed that the hardening soil model is more logically indicative of the difference between the unloading hardness and loading hardness of the excavation displacement pattern than Mohr-Coulumb constitutive model. Therefore, it is recommended that more advanced constitutive models such as the hardening soil model be used as they are capable of modeling more constitute aspects of the soil.

Keywords:

Numerical modeling , displacement field , advanced constitutive model , Plaxis software