A New Procedure for Simulating Active Lateral Force in Spatially Variable Clay Modeled by Anisotropic Random Field

2015 ◽  
Vol 31 (4) ◽  
pp. 381-390
Author(s):  
Y.-G. Hu ◽  
J. Ching
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shear Strength ◽  
Random Field ◽  
Retaining Wall ◽  
Lateral Force ◽  
Undrained Shear Strength ◽  
Undrained Shear ◽  
Element Method

AbstractA new procedure for simulating the active lateral force (Pa) is proposed for clays with anisotropic spatially variable undrained shear strength (su). With the proposed procedure, the Pa samples can be simulated without the use of the random field finite element method (RFEM). It requires only simple algebraic calculations and chart checking. Two retaining wall examples with isotropic or anisotropic random field are used to demonstrate the effectiveness of the proposed procedure.

scholarly journals Assessment of Rectangular Cavity in Concrete Gravity Retaining Wall using Finite Element Method

2019 ◽  
Vol 8 (4) ◽  
pp. 2656-2661
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Cross Section ◽  
Retaining Wall ◽  
Rectangular Cavity ◽  
Gravity Retaining Wall ◽  
The Cross ◽  
Conditions Of Stability ◽  
Element Method

The design of the Gravity retaining wall (GRW) is a trial and error process. Prevailing conditions of backfill are used to determine the profile of GRW, which proceeds with the selection of provisional dimensions. The optimum section is having factors of safety of stability higher than the allowable values and stresses in the cross-section smaller than permissible. The cross-section is designed to fulfill conditions of stability, subjected to very low stresses. The strength of the material, which is provided in the cross-section remains unutilized. A computer program is developed to find stresses at various locations on the cross-section of GRW using the Finite Element Method (FEM). A discontinuity in the form of a rectangular cavity is introduced in the cross-section of GRW to optimize it. The rectangular cavity is introduced in the cross-section of GRW at different locations. An attempt is made in this paper to find the stress distribution in the gravity retaining wall cross-section and to study the effect of the rectangular cavity on the stress distribution. Two cases representing different locations are considered to study the effect of the cavity. The location of the cavity is distinguished by the parameter w, the effects of cases with varied was 0.2305 (Case-I) and 0.1385 (Case-II) are observed. The cavity, which is provided not only makes the wall structurally efficient but also economically feasible.

Probabilistic failure envelopes of strip foundations on soils with non-stationary characteristics of undrained shear strength

Géotechnique ◽  
2021 ◽  
pp. 1-44
Author(s):  
Zhichao Shen ◽  
Qiujing Pan ◽  
Siau Chen Chian ◽  
Susan Gourvenec ◽  
Yinghui Tian
Keyword(s):  
Shear Strength ◽  
Random Field ◽  
Numerical Models ◽  
Undrained Shear Strength ◽  
Considerable Effect ◽  
Failure Envelopes ◽  
Autocorrelation Distance ◽  
Stationary Random Field ◽  
Constant Coefficient Of Variation ◽  
Undrained Shear

This paper investigates probabilistic failure envelopes of strip foundations on spatially variable soils with profiles of undrained shear strength su linearly increasing with depth using the lower bound random finite element limit analysis. The spatially variable su is characterised by a non-stationary random field with linearly increasing mean and constant coefficient of variation (COV) with depth. The deterministic uniaxial capacities and failure envelopes are firstly derived to validate numerical models and provide a reference for the subsequent probabilistic analysis. Results indicate that the random field parameters COVsu (COV of su) and Δ (dimensionless autocorrelation distance) have a considerable effect on the probabilistic normalised uniaxial capacities which alters the size of probabilistic failure envelopes. However, COVsu and Δ have an insignificant effect on the shape of probabilistic failure envelopes is observed in the V-H, V-M and H-M loading spaces, such that failure envelopes for different soil variabilities can be simply scaled by the uniaxial capacities. In contrast to COVsu and Δ, the soil strength heterogeneity index κ = μkB/μsu0 has the lowest effect on the probabilistic normalised uniaxial capacity factors but the highest effect on the shape of the probabilistic failure envelopes. A series of expressions are proposed to describe the shape of deterministic and probabilistic failure envelopes for strip foundations under combined vertical, horizontal and moment (V-H-M) loading.

scholarly journals CPT-Based Probabilistic Characterization of Undrained Shear Strength of Clay

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Mi Tian ◽  
Xiaotao Sheng
Keyword(s):  
Shear Strength ◽  
Correlation Function ◽  
Random Field ◽  
Site Investigation ◽  
Undrained Shear Strength ◽  
Bayesian Approaches ◽  
Probabilistic Characterization ◽  
Undrained Shear

Applying random field theory involves two important issues: the statistical homogeneity (or stationarity) and determination of random field parameters and correlation function. However, the profiles of soil properties are typically assumed to be statistically homogeneous or stationary without rigorous statistical verification. It is also a challenging task to simultaneously determine random field parameters and the correlation function due to a limited amount of direct test data and various uncertainties (e.g., transformation uncertainties) arising during site investigation. This paper presents Bayesian approaches for probabilistic characterization of undrained shear strength using cone penetration test (CPT) data and prior information. Homogeneous soil units are first identified using CPT data and subsequently assessed for weak stationarity by the modified Bartlett test to reject the null hypothesis of stationarity. Then, Bayesian approaches are developed to determine the random field parameters and simultaneously select the most probable correlation function among a pool of candidate correlation functions within the identified statistically homogeneous layers. The proposed approaches are illustrated using CPT data at a clay site in Shanghai, China. It is shown that Bayesian approaches provide a rational tool for proper determination of random field model for probabilistic characterization of undrained shear strength with consideration of transformation uncertainty.

Seismic Analysis of Soil Nailed Wall Using Finite Element Method

2012 ◽  
Vol 535-537 ◽  
pp. 2027-2031 ◽  
Author(s):  
Jian Chun Wu ◽  
Rong Shi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Seismic Analysis ◽  
Retaining Wall ◽  
Plastic Behavior ◽  
Soil Nailing ◽  
Nonlinear Fem ◽  
Elastic Plastic ◽  
Flexible Retaining Wall ◽  
Element Method

Using dynamic elastic-plastic finite element method, on the base of works together and interaction between loess and flexible retaining wall, 3-D nonlinear FEM (ADINA) is used to analyze and discussed the dynamic response of slope protected by soil nailing retaining wall under the EL-Centro and man-made Lanzhou accelerogram. A model that is capable of simulating the nonlinear static and dynamic elastic-plastic behavior of soil is used to model the soil, and a bilinear elastic-plastic model that has hardening behavior is used to model the soil nailing. Friction-element is employed to describe the soil-structure interaction behavior.The results show that the method is safe and credible. The results of the FEM dynamic analysis can be a useful reference for engineers of the design and construction of the soil nailed wall.

Sign in / Sign up

Export Citation Format

Share Document