Liquefaction analysis of Duncan Dam using strength ratios

2006 ◽  
Vol 43 (5) ◽  
pp. 484-499 ◽  
Author(s):  
Scott M Olson
Keyword(s):  
Shear Strength ◽  
Large Strain ◽  
Analysis Procedure ◽  
Primary Analysis ◽  
Seismic Safety ◽  
Safety Studies ◽  
Penetration Tests ◽  
Yield Shear Strength ◽  
Good Agreement ◽  
Liquefaction Analysis

B.C. Hydro performed extensive seismic safety studies for Duncan Dam in the late 1980s and early 1990s. The results of these studies indicated that Duncan Dam was reasonably safe from liquefaction-induced failure. A recently proposed liquefaction analysis procedure that uses strength ratios to assess liquefaction triggering and post-triggering stability was used to revisit the liquefaction analysis of Duncan Dam. When compared to the detailed field and analytical studies performed by B.C. Hydro, the proposed liquefaction analysis procedure predicts: (i) similar zones of liquefaction within a contractive unit of foundation sand; (ii) similar shear strengths at the triggering of liquefaction (yield shear strength) and at large strain (liquefied shear strength); and (iii) similar post-triggering factors of safety for slope stability. The good agreement suggests that the strength ratio based liquefaction analysis approach is relatively robust and is suitable for screening level studies for large projects or may serve as the primary analysis procedure for less complex projects.Key words: liquefaction, liquefied shear strength, yield shear strength, laboratory tests, penetration tests, Duncan Dam.

scholarly journals Calibration of Finn Model and UBCSAND Model for Simplified Liquefaction Analysis Procedures

2021 ◽  
Vol 11 (11) ◽  
pp. 5283
Author(s):  
Jui-Ching Chou ◽  
Hsueh-Tusng Yang ◽  
Der-Guey Lin
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Structural Damage ◽  
Simulation Analysis ◽  
Constitutive Models ◽  
Soil Liquefaction ◽  
Analysis Procedure ◽  
Liquefaction Resistance ◽  
Simplified Procedure ◽  
Liquefaction Analysis

Soil-liquefaction-related hazards can damage structures or lead to an extensive loss of life and property. Therefore, the stability and safety of structures against soil liquefaction are essential for evaluation in earthquake design. In practice, the simplified liquefaction analysis procedure associated with numerical simulation analysis is the most used approach for evaluating the behavior of structures or the effectiveness of mitigation plans. First, the occurrence of soil liquefaction is evaluated using the simplified procedure. If soil liquefaction occurs, the resulting structural damage or the following mitigation plan is evaluated using the numerical simulation analysis. Rational and comparable evaluation results between the simplified liquefaction analysis procedure and the numerical simulation analysis are achieved by ensuring that the liquefaction constitutive model used in the numerical simulation has a consistent liquefaction resistance with the simplified liquefaction analysis procedure. In this study, two frequently used liquefaction constitutive models (Finn model and UBCSAND model) were calibrated by fitting the liquefaction triggering curves of most used simplified liquefaction analysis procedures (NCEER, HBF, JRA96, and T-Y procedures) in Taiwan via FLAC program. In addition, the responses of two calibrated models were compared and discussed to provide guidelines for selecting an appropriate liquefaction constitutive model in future projects.

Residual shear strength of fine-grained soils and soil–solid interfaces at low effective normal stresses

2015 ◽  
Vol 52 (2) ◽  
pp. 198-210 ◽  
Author(s):  
Hisham T. Eid ◽  
Ruslan S. Amarasinghe ◽  
Khaled H. Rabie ◽  
Dharma Wijewickreme
Keyword(s):  
Shear Strength ◽  
Large Strain ◽  
Laboratory Research ◽  
Normal Stresses ◽  
Interface Shear ◽  
Residual Shear Strength ◽  
Fine Grained ◽  
Solid Interface ◽  
Wide Range ◽  
Shear Area

A laboratory research program was undertaken to study the large-strain shear strength characteristics of fine-grained soils under low effective normal stresses (∼3–7 kPa). Soils that cover a wide range of plasticity and composition were utilized in the program. The interface shear strength of these soils against a number of solid surfaces having different roughness was also investigated at similar low effective normal stress levels. The findings contribute to advancing the knowledge of the parameters needed for the design of pipelines placed on sea beds and the stability analysis of shallow soil slopes. A Bromhead-type torsional ring-shear apparatus was modified to suit measuring soil–soil and soil–solid interface residual shear strengths at the low effective normal stresses. In consideration of increasing the accuracy of assessment and depicting the full-scale field behavior, the interface residual shear strengths were also measured using a macroscale interface direct shear device with a plan interface shear area of ∼3.0 m2. Correlations are developed to estimate the soil–soil and soil–solid interface residual shear strengths at low effective normal stresses. The correlations are compared with soil–soil and soil–solid interface drained residual shear strengths and correlations presented in the literature.

Thermomechanical Behavior of Low CTE Metal-Matrix Composites Fabricated Through Ultrasonic Additive Manufacturing

2012 ◽  
Author(s):  
Ryan Hahnlen ◽  
Marcelo J. Dapino
Keyword(s):  
Shear Strength ◽  
Additive Manufacturing ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Large Strain ◽  
Matrix Composites ◽  
Interface Shear ◽  
Mechanical Coupling ◽  
Ultrasonic Additive Manufacturing

Shape memory and superelastic NiTi are often utilized for their large strain recovery and actuation properties. The objective of this research is to utilize the stresses generated by pre-strained NiTi as it is heated in order to tailor the CTE of metal-matrix composites. The composites studied consist of an Al 3003-H18 matrix with embedded NiTi ribbons fabricated through an emerging rapid prototyping process called Ultrasonic Additive Manufacturing (UAM). The thermally-induced strain of the composites is characterized and results show that the two key parameters in adjusting the effective CTE are the NiTi volume fraction and prestrain of the embedded NiTi. From the observed behavior, a constitutive composite model is developed based constitutive SMA models and strain matching composite models. Additional composites were fabricated to characterize the NiTi-Al interface through EDS and DSC. These methods were used to investigate the possibility of metallurgical bonding between the ribbon and matrix and determine interface shear strength. Interface investigation indicates that mechanical coupling is accomplished primarily through friction and the shear strength of the interface is 7.28 MPa. Finally, using the developed model, a composite was designed and fabricated to achieve a near zero CTE. The model suggests that the finished composite will have a zero CTE at a temperature of 135°C.

Effect of various treatments on consolidation of oil sands fluid fine tailings

2018 ◽  
Vol 55 (8) ◽  
pp. 1059-1066 ◽  
Author(s):  
G. Ward Wilson ◽  
Louis K. Kabwe ◽  
Nicholas A. Beier ◽  
J. Don Scott
Keyword(s):  
Shear Strength ◽  
Oil Sands ◽  
Large Strain ◽  
Regulatory Requirements ◽  
Freeze Thaw ◽  
Treatment Processes ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Solids Content ◽  
And Storage

Regulatory policy and regulations in Alberta require oil sands companies to reduce their production and storage of fluid fine tailings by creating deposits that can be reclaimed in a timely manner. To meet the regulatory requirements, some companies are adding flocculants to the fluid fine tailings and then using thickeners, inline flocculation or centrifuges to increase the solids content. Freeze–thaw and drying processes are then used to further dewater the tailings. The effects of flocculating, thickening, and freeze–thaw treatments were investigated by performing large-strain consolidation and shear strength tests on these treated fluid fine tailings. The consolidation and shear strength results were then compared with those of untreated fluid fine tailings. All of the treatments increased the hydraulic conductivity of the fluid fine tailings to some degree, but had little to no effect on the compressibility and shear strength. The effects of the treatment processes are discussed and evaluated.

scholarly journals Radar Cross-Section Formulation of a Shell-Shaped Projectile Using Modified PO Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Mohammad Asif Zaman ◽  
Md. Abdul Matin
Keyword(s):  
Differential Geometry ◽  
Cross Section ◽  
Current Density ◽  
Surface Current ◽  
Radar Cross Section ◽  
Analysis Procedure ◽  
Physical Optics ◽  
Surface Current Density ◽  
Filtering Method ◽  
Good Agreement

A physical optics based method is presented for calculation of monostatic Radar Cross-Section (RCS) of a shell-shaped projectile. The projectile is modeled using differential geometry. The paper presents a detailed analysis procedure for RCS formulation using physical optics (PO) method. The shortcomings of the PO method in predicting accurate surface current density near the shadow boundaries are highlighted. A Fourier transform-based filtering method is proposed to remove the discontinuities in the approximated surface current density. The modified current density is used to formulate the scattered field and RCS. Numerical results are presented comparing the proposed method with conventional PO method. The results are also compared with published results of similar objects and found to be in good agreement.

Interpretation of cone penetration tests. Part II: Clay

1983 ◽  
Vol 20 (4) ◽  
pp. 734-745 ◽  
Author(s):  
P. K. Robertson ◽  
R. G. Campanella
Keyword(s):  
Shear Strength ◽  
Friction Angle ◽  
Companion Paper ◽  
Deformation Characteristics ◽  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Cone Penetration Testing ◽  
Personal Experiences ◽  
Penetration Tests

This paper is the second of two parts and presents a summarized work guide for practicing engineers for interpretation of parameters for undrained conditions during the cone penetration test such as, undrained shear strength, overconsolidation ratio, and deformation characteristics of clay. The advantages, use, and interpretation of the piezometer cone are also discussed. Factors that influence the interpretations are discussed and guidelines provided. The companion paper, Part I: Sand, considers drained conditions during the test and summarizes interpretation of parameters such as relative density, friction angle, and deformation characteristics of sand. The authors' personal experiences and current recommendations are included. Keywords: static cone penetration testing, in-situ, interpretation, shear strength, modulus, stress history, pore pressures, permeability, consolidation.

A new design approach for the determination of the buckling load of rectangular plates

2012 ◽  
Vol 227 (7) ◽  
pp. 1417-1428
Author(s):  
H Ahmed ◽  
JF Durodola ◽  
RG Beale
Keyword(s):  
Analysis Procedure ◽  
Preliminary Design ◽  
Rectangular Plates ◽  
Finite Element Analyses ◽  
Support Condition ◽  
Plate Edge ◽  
Buckling Loads ◽  
Plate Buckling ◽  
Good Agreement

The objective of this article is to introduce and assess a new plate buckling analysis procedure which can be used for quick, approximate analysis of buckling loads in preliminary design. The method is applied to a range of plate edge support condition combinations including many where results are not readily available. The results obtained using the new procedure were compared against theoretical formulae available in the literature and by finite element analyses with good agreement.

scholarly journals Seismic collapse assessment of new European single-story RC precast buildings with weak connections

2020 ◽  
Vol 18 (15) ◽  
pp. 6661-6686
Author(s):  
Maddalena Cimmino ◽  
Gennaro Magliulo ◽  
Gaetano Manfredi
Keyword(s):  
Shear Strength ◽  
Failure Modes ◽  
Plastic Hinge ◽  
Concrete Cover ◽  
Eurocode 8 ◽  
Structural Level ◽  
Seismic Safety ◽  
Strength Failure ◽  
Precast Buildings ◽  
Lateral Displacements

Abstract Capacity design, according to the modern seismic building codes, requires the application of specific rules and construction details in order to prevent brittle failure modes at material, element and structural level. In particular, with reference to single-story precast reinforced concrete structures with columns joined by pinned beams, the Italian seismic building code, following the Eurocode 8 general principles, requires that beam-to-column connection should be designed in order to avoid the connection failure before the formation of the plastic hinge at the column base. However, no specific details are provided in order to reach such a performance. Recent European earthquakes showed that seismic performance of beam-to-column dowel connections can be very poor. Hence, for European typical dowel beam-to-column connections, this study aims to investigate: (a) possible connection configurations obtained according to seismic design; (b) possible failure modes involving connection elements (steel dowel, transversal steel reinforcement, dowel concrete cover); (c) how available formulations are able to describe such failure modes and the related shear strength; (d) influence of connection failure on the global seismic safety at collapse of new designed single-story RC precast buildings. The reference buildings and beam-to-column connections are designed considering different geometrical layouts of the primary structure and different seismic hazard levels, i.e. four sites and two soil types. Structural capacity is estimated considering global, i.e. related to column plastic hinge degradation measured in terms of top lateral displacements, and local, i.e. related to connection shear strength, failure modes. Nonlinear multi-stripe analyses are performed for the seismic assessment.

Postliquefaction Deformation of Embankments and Effects on Restraining Piles

1998 ◽  
Vol 1633 (1) ◽  
pp. 19-25
Author(s):  
W.D. Liam Finn
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Strength ◽  
Prestressed Concrete ◽  
Large Strain ◽  
Limit Equilibrium ◽  
Safety Evaluation ◽  
Equilibrium Analysis ◽  
Element Analysis ◽  
Seismic Safety

There are three levels of analysis for assessing the postliquefaction stability of embankments: limit equilibrium analysis using residual strength, Newmark sliding block analysis using residual strength, and finite element large strain displacement analysis. The first two types are well known and often used. In recent years, finite element analysis has been used increasingly for important projects involving life safety and large remediation costs. The application of finite element analysis is illustrated by two case histories—failure of a river protection dike in Japan, and the seismic safety evaluation and subsequent remediation of Sardis Dam in Mississippi. The latter example is particularly relevant to pile-supported abutments because the upstream slope of the dam was nailed to a stable foundation layer using prestressed concrete piles. The determination of the static and dynamic moments and shears in these piles would not have been possible without the finite element analysis. A crucial problem affecting the reliability of all methods of analysis is determining the appropriate value for the residual strength.

Numerical Simulation of Debris Bed Relocation Behavior in Sodium-Cooled Fast Reactor

2018 ◽  
Author(s):  
Chunming Teng ◽  
Bin Zhang ◽  
Jianqiang Shan
Keyword(s):  
Shear Strength ◽  
Fast Reactor ◽  
Simulation Analysis ◽  
Soil Mechanics ◽  
Great Influence ◽  
Transition Process ◽  
Effective Implementation ◽  
Debris Particles ◽  
Cooling Ability ◽  
Good Agreement

For the core disruptive accident (CDA) of sodium-cooled fast reactor (SFR), the molten fuel or steel is solidified into debris particles which form debris bed in the lower plenum. When the boiling occurs inside debris bed, the flow of coolant and vapor makes debris relocated and flattened, which called debris relocation. The thickness of debris bed has great influence to the cooling ability of fuel debris in low plenum. To ensure the effective implementation of the in-vessel retention (IVR), it’s very necessary to evaluate the transient changes of shape and thickness in relocation behavior for CDA simulation analysis. To simulate relocation behavior, a debris relocation model based on COMMEN code was developed in this paper. The debris relocation model was established based on the extrapolation of the shear strength mechanism, which was originally proposed and widely applied in soil mechanics filed. Shear strength is a function of the particles’ density and position. Debris bed is fluidized only when the shear stress in particle unit is larger than shear strength of debris particles. By integrating the debris relocation model into the COMMEN code, the transition process of the bed in depressurization experiments was simulated and compared against the experimental results. Good agreement shows that the debris relocation model presented in this paper can reasonably simulate the relocation behavior.

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