Intergranular-strain elastic model for recent stress history effects on clay

2020 ◽  
Vol 118 ◽  
pp. 103316 ◽  
Author(s):  
Zhenhao Shi ◽  
Maosong Huang
2019 ◽  
Vol 7 (6) ◽  
pp. 170 ◽  
Author(s):  
Ben He ◽  
Yongqing Lai ◽  
Lizhong Wang ◽  
Yi Hong ◽  
Ronghua Zhu

Scouring of soil around large-diameter monopile will alter the stress history, and therefore the stiffness and strength of the soil at shallow depth, with important consequence to the lateral behavior of piles. The existing study is mainly focused on small-diameter piles under scouring, where the soil around a pile is analyzed with two simplified approaches: (I) simply removing the scour layers without changing the strength and stiffness of the remaining soils, or (II) solely considering the effects of stress history on the soil strength. This study aims to investigate and quantify the scour effect on the lateral behavior of monopile, based on an advanced hypoplastic model considering the influence of stress history on both soil stiffness and strength. It is revealed that ignorance about the stress history effect (due to scouring) underestimates the extent of the soil failure wedge around the monopile, while overestimates soil stiffness and strength. As a result, a large-diameter pile (diameter D = 5 m) in soft clay subjected to a souring depth of 0.5 D has experienced reductions in ultimate soil resistance and initial stiffness of the p-y curves by 40% and 26%, and thus an increase of pile head deflection by 49%. Due to the inadequacy to consider the stress history effects revealed above, the existing approach (I) has led to non-conservative estimation, while the approach (II) has resulted in an over-conservative prediction.


Author(s):  
Priyanka Sarker ◽  
Erol Tutumluer

This paper presents a stress-history-based approach to predict the deformation basins of airport pavements subjected to heavy aircraft loading applied in sequential wanders. Multi-depth deflectometer data from full-scale aircraft landing gear tests conducted at the National Airport Pavement Test Facility built by the Federal Aviation Administration are used to create individual pass residual deformation transverse profiles. The computed residual deformation profiles are further corrected for stress-history effects to predict rut in the selected test sections. The developed model focuses on using the previous load location and stress history of the soil element to develop the deformations in that element. Despite the unavailability of the surface transverse profile data measured in the field at different passes, the initial attempt of the model can closely predict the deformation profile similar to width and shape expected in the field. And after the stress-history effects are accounted for, the initially calculated rut depth decreases significantly to match the final contour basin of the test sections extracted from the post traffic trenching. The advantage of using the stress-history-effects-based rut prediction tool is that it can allow any combination of wander positions and sequences of load applications to be accounted for their effects on the final surface rut development.


Author(s):  
Ashutosh Sutra Dhar ◽  
Abu Hena Muntakim

Nonlinear finite element analysis of axi-symmetrically dented/wrinkled pipe has been presented in this paper. The pipe including surrounding soil was modelled using three different approaches to indicate the effects of modelling approaches on the simulation of pipe behavior. In the first approach, pipe was modelled with the geometry of the dented/wrinkled pipe without consideration of any residual stress and stress history. In the second approach, residual stress was applied at the nodal points of the pipe geometry modelled as in the first approach. In the third approach, a dent/wrinkle was created on the pipe wall through applying nodal displacements to include residual stress as well as the stress history effects. The analysis revealed that the first approach provides an un-conservative estimation of the pipe capacity. The second approach provides a reasonable estimation of the pipe capacity for elastic perfectly plastic material. However, the second approach provides a conservative estimation for strain hardening material, since pipe stress history is not considered. For strain hardening materials, both residual stress and the stress history should be considered for the simulation of the pipe behavior. The surrounding soil appears not to contribute to the capacity of the pipes under the loading conditions investigated.


IFCEE 2021 ◽  
2021 ◽  
Author(s):  
A. J. Aparicio-Ortube ◽  
Luis G. Arboleda-Monsalve ◽  
David G. Zapata-Medina ◽  
Larry Jones

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