Seismic performance of deep excavation restrained by guardian truss structures system using quasi-static approach

Abstract

The control of deformation and stability of the deep excavation walls under seismic and static loads is one of the most important issues in geotechnical engineering. Therefore, in the present study, using the finite element method and taking into account Hardening soil's behavioural model, the effect of different parameters affecting the performance of the deep excavation walls with the guardian truss structures using quasi-static analysis and its comparison with static analysis has been performed. According to the most important results, increasing in the geotechnical parameters of soil such as cohesion, friction angle and elastic modulus will reduce the maximum horizontal displacement in the vertical trench wall. Besides, the maximum settling in the adjacent ground and the maximum swelling in the bottom of the excavation will be reduced. In this way, the improvement in soil resistance parameters will increase the safety factor. Conversely, by increasing the horizontal distance between the trusses, the maximum horizontal displacement and the maximum settling in the adjacent ground and the maximum swelling in the bottom of the excavation will increase and the safety factor will be reduced. Also, the findings from this research show that by increasing the horizontal seismic acceleration coefficient (Kh) and as the construction stages progress, the maximum horizontal displacement of the wall, the maximum settling of the adjacent ground of the wall and the maximum swelling on the bottom of the trench increase and the safety factor will decrease. As well as, the results obtained from the quasi-static seismic analysis of the vertical trench restrained by the guardian truss structure such as the maximum horizontal displacement of the vertical trench wall and the maximum settling in the adjacent ground and the maximum swelling of the bottom of the excavation are much more than the static analysis.

Numerical Validation of Fully Coupled Nonlinear Seismic Soil–Pile–Structure Interaction

“…The lateral boundary of the model should be sufficiently far from the model's lower limit to minimize the impact of boundaries on the numerical results. The displacement and stress contours in the finite element software confirm that the accepted distance is enough [40,41]. The finite element meshes are built much finer (cross-shaped) near the pile, as seen in Figure 1.…”

Establishment of Localized Utilization Parameters for Numerical Simulation Analysis Applied to Deep Excavations

“…Similarly, some foreign scholars have applied the finite element method to analyze lateral displacements of retaining structures, yielding satisfactory results [12][13][14][15]. Recently, Maleki et al also provided many important conclusions for reference in the field of numerical analysis modeling using the finite element method [16][17][18].…”

“…From an international perspective, scholars such as Maleki et al have stated: "The distance from the lateral boundary of the model and the distance between the lower bound of the model from the top should be taken as sufficient so that the effects of the boundaries in the numerical model on the results are minimized. The displacement and the stress contours in the finite element software indicate that this distance is sufficient" [39][40][41].…”

A multi-objective optimization evaluation model for seismic performance of slopes reinforced by pile-anchor system

“…The numerical model has a great influence on the simulation results [36][37][38] , and we make appropriate simplifications to construct the numerical model on the basis of the above prototype slope. The bedding slope angle is 45°, the rock dip angle is 20°, five weak interlayers with a thickness of 0.2 m are set in the upper part, and the bottom is bedrock.…”

“…Hence, we set the grid size to 0.8 m, thus ensuring the complete propagation of seismic waves in the medium. Note that the meshing refinement should be discontinued after checking that the results do not change [40][41][42] . In summary, 18,630 nodes are generated, and 15,000 grid cells are delineated in the current model (Fig.…”