A simplified small-strain soil model, referred to herein as the modified pseudoplasticity (MPP) model, developed based on the small-strain behavior of clay measured from the triaxial tests is evalu...

Evaluation of a simplified small-strain soil model for analysis of excavation-induced movements

Probability of serviceability failure in a braced excavation in a spatially random field: Fuzzy finite element approach

A simplified method for predicting ground settlement profiles induced by excavation in soft clay

This paper presents the performance of an excavation with cross walls based on field observations and numerical analysis results. A small strain constitutive model was used in the analysis. By comparing the movements of the real case with the same case but without cross walls installed, the effectiveness of cross walls was thus evaluated. Results indicate that the movements in the case history were substantially reduced by the installation of cross walls. The maximum wall deflection and ground settlement at a place where the cross wall was installed was reduced by about 75 and 82%, respectively. The movements near the diaphragm wall or cross wall corner were relatively small, compared with those far away from the corner. The diaphragm wall still had some deflection at the sections where cross walls were installed and the amount of deflection was close to that from linear elastic analysis. It is justified that slime between cross walls and diaphragm walls during trench excavation was fully cleaned.

Performance of Excavations with Cross Walls

Investigating the effect of soil models on deformations caused by braced excavations through an inverse-analysis technique

The original hyperbolic model uses the stress level criterion to differentiate the state between the primary loading and unloading/reloading states. This simple stress level criterion cannot take into account the rotation of principal stresses or the anisotropic soil behavior. In this study, the concept of the plasticity theory is employed in a hyperbolic model. The strength and yield functions derived based on Lo's equation are used to differentiate Young's moduli between primary loading and unloading/reloading states. The strength criterion can estimate the undrained shear strengths in various directions with good accuracy, based on the laboratory test results in the literature. An excavation case with complete field observations is then studied using the finite element method with the modified and original hyperbolic models. Analysis results show that the proposed method can give better prediction for wall deflection, ground surface settlement, wall bending moment, total lateral earth pressure and bottom heave, compared with the original model. (A)

P G Hsieh

Papers

Use of the modified hyperbolic model in excavation analysis under undrained condition