Finite Element Simulation of Deep Excavation Failures

Abstract

Deep excavations play an increasingly greater role in the development of urban transportation infrastructure facilities such as subway systems and underground space. This paper presents the results of finite element simulations of two deep excavations in soft cohesive soils involving collapse. An enhanced bounding surface soil model characterizes the cohesive soils. The model is anisotropic and is formulated with a non-associative flow rule, but can be degenerated to an isotropic model with associative flow. The results of the excavation simulations give insight into the ground response in terms of lateral wall deflections, ground surface settlements, wall bending moments, and strut force developments. Anisotropic and isotropic versions of model showed differences in simulated results. The insignificant difference in results between the associative and non-associative versions of enhanced bounding surface model is illustrated, but it is expected that, in general, the use of non-associative flow rule will provide a more realistic simulation.

Adaptive anisotropic constitutive modeling of natural clays

“…Comparison of experimental data with the model simulations (Figure 10) suggests that = 1.3 (by considering = 33) can lead to more compatible predictions and therefore, calibration of parameters is carried out by assuming = 1.3. It should be noted that a similar value for is used in the simulation of the undrained isotropic triaxial test of TSC in Hung et al 61 …”

Computational implementation of bounding surface model and its verification through cavity benchmark problems

“…It has recently been implemented into the geotechnical analysis commercial finite element program PLAXIS for simulating deep excavation problems. [ 20,21 ]…”

Lesson learned from retaining wall failures: a geotechnical disaster

“…This article would focus on failures of retaining wall, either for excavation or fill purposes because most of the excavations are constructed in a dense urban area, where the risk of losing a human life is relatively high. In past decades, several major excavation failures were reported in the literature, such as Nicoll Highway excavation in Singapore [3,4,5], Shipai excavation and Rebar Broadway excavation in Taipei [6,7,8,9,10,11]. In addition, a case of excessive deformations induced by excavation also recorded in Jakarta back in 1991 and causing the demolishment of the affected building.…”