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Performance Of Resin Injection Ground Improvement In Silty Sand Based On Blast-Induced Liquefaction Testing In Christchurch, New Zealand, David Harold Blake Apr 2022

Performance Of Resin Injection Ground Improvement In Silty Sand Based On Blast-Induced Liquefaction Testing In Christchurch, New Zealand, David Harold Blake

Theses and Dissertations

Polyurethane resin injection is a treatment being considered as a replacement for traditional methods of ground improvement. It has been used to re-level foundations and concrete slabs that have settled over time. Additional claimed benefits of the treatment have been noted recently, including improved factors of safety against soil liquefaction and reduced earthquake-induced settlements. To investigate the capability of the polyurethane resin injection treatment to mitigate liquefaction, two full-scale blast liquefaction tests were performed; one test was conducted in an improved panel (IP), an 8 m circular area treated with the polyurethane resin in a 1.2 m triangular grid from …


Gravel Liquefaction Assessment With The Dynamic Penetration Test At Non-Liquefaction Sites In Valdez, Alaska And L'Aquila, Italy, Nicholas James Linton Apr 2021

Gravel Liquefaction Assessment With The Dynamic Penetration Test At Non-Liquefaction Sites In Valdez, Alaska And L'Aquila, Italy, Nicholas James Linton

Theses and Dissertations

The development of a reliable, and cost-effective in-situ method for characterizing the liquefaction potential of gravelly soils is a considerable challenge for engineers and researchers. The ability to accurately characterize the liquefaction potential of gravelly soils is an important consideration at port facilities and dams for example. The Dynamic Penetration Test (DPT) provides a reliable and cost-effective method for evaluating the liquefaction resistance of gravelly soils. Probabilistic liquefaction triggering curves based on DPT field data have been developed from data collected at 47 sites in China. However, using the DPT-based liquefaction curves for locations outside of the Chengdu plain in …


Blast-Induced Liquefaction And Downdrag Development On A Micropile Foundation, Cameron Mark Lusvardi Dec 2020

Blast-Induced Liquefaction And Downdrag Development On A Micropile Foundation, Cameron Mark Lusvardi

Theses and Dissertations

Frequently, deep foundations extend through potentially liquefiable soils. When liquefaction occurs in cohesionless soils surrounding a deep foundation, the skin-friction in the liquefied layer is compromised. After cyclical forces suspend and pore pressures dissipate, effective stress rebuilds and the liquefied soil consolidates. When the settlement of the soil exceeds the downward movement of the foundation, downdrag develops. To investigate the loss and redevelopment of skin-friction, strain was measured on an instrumented micropile during a blast-induced liquefaction test in Mirabello, Italy. The soil profile where the micropile was installed consisted of clay to a depth of 6m underlain by a medium …


Performance Of A Full-Scale Rammed Aggregate Pier Group In Silty Sand Based On Blast-Induced Liquefaction Testing In Emilia-Romagna, Italy, Paul Joseph Walsh Andersen Jun 2020

Performance Of A Full-Scale Rammed Aggregate Pier Group In Silty Sand Based On Blast-Induced Liquefaction Testing In Emilia-Romagna, Italy, Paul Joseph Walsh Andersen

Theses and Dissertations

To investigate the liquefaction mitigation capability of Rammed Aggregate Piers® (RAP) in silty sand, blast liquefaction testing was performed at a soil profile treated with a full-scale RAP group relative to an untreated soil profile. The RAP group consisted of 16 piers in a 4x4 arrangement at 2 m center-to-center spacing extending to a depth of 9.5 m. Blasting around the untreated area induced liquefaction (ru ≈1.0) from 3 m to 11 m depth, producing several large sand boils, and causing settlement of 10 cm. In contrast, installation of the RAP group reduced excess pore water pressure (ru ≈0.75), eliminated …


Development Of A Simplified Performance-Based Procedure For Assessment Of Liquefaction Triggering For The Cone Penetration Test, Jenny Lee Blonquist Apr 2020

Development Of A Simplified Performance-Based Procedure For Assessment Of Liquefaction Triggering For The Cone Penetration Test, Jenny Lee Blonquist

Theses and Dissertations

Soil liquefaction can cause devastating damage and loss and is a serious concern in civil engineering practice. One method for evaluating liquefaction triggering potential is a risk-targeted probabilistic approach that has been shown to provide more consistent and accurate estimates of liquefaction risk than traditional methods. This approach is a “performance-based” procedure which is based off of the performance-based earthquake engineering (PBEE) framework developed by the Pacific Earthquake Engineering Research (PEER) Center. Unfortunately, due to its complexity, performance-based liquefaction assessment is not often used in engineering practice. However, previous researchers have developed a simplified performance-based procedure which incorporates the accuracy …


Analysis Of Applied Modifications To A Cone Penetration Test-Based Lateral Spread Displacement Prediction Model, Alexander Edward Corob Dec 2019

Analysis Of Applied Modifications To A Cone Penetration Test-Based Lateral Spread Displacement Prediction Model, Alexander Edward Corob

Theses and Dissertations

This study set out to examine the effectiveness and reliability of six modifications to the Zhang et al. (2004) CPT-based lateral spread model. A regression analysis, distribution charts, and a discriminant analysis are performed to determine how effective the modifications are on the model. From the comparisons and statistical analysis performed in this study, application of these modifications reduces over-predictions from strain-based prediction methods. Unfortunately, the tendency to under-predict displacements on average is also increased.


Development Of A Simplified Performance-Based Procedure For Assessment Of Post-Liquefaction Settlement Using The Cone Penetration Test, Jingwen He Jul 2019

Development Of A Simplified Performance-Based Procedure For Assessment Of Post-Liquefaction Settlement Using The Cone Penetration Test, Jingwen He

Theses and Dissertations

Earthquake-induced liquefaction can cause severe damage to infrastructure is a serious concern in civil engineering practice. Post-liquefaction settlement is one of the common effects of liquefaction. The ability to predict and quantify post-liquefaction free-field settlement is a crucial part of seismic design. Many approaches have been developed during the past 50 years to perform liquefaction hazard analysis. The performance-based earthquake engineering (PBEE) framework developed by the Pacific Earthquake Engineering Research (PEER) center is a probabilistic framework that can provide a more accurate and complete seismic hazard analysis than other traditional methods. However, the PBEE framework is not widely used in …


Development Of A Simplified Analysis Approach For Predicting Pile Deflections Of Piers Subjected To Lateral Spread Displacements And Application To A Pier Damaged During The 2010 Maule, Chile, M8.8 Earthquake, Logan Matthew Palmer Dec 2018

Development Of A Simplified Analysis Approach For Predicting Pile Deflections Of Piers Subjected To Lateral Spread Displacements And Application To A Pier Damaged During The 2010 Maule, Chile, M8.8 Earthquake, Logan Matthew Palmer

Theses and Dissertations

The 2010, moment magnitude 8.8 earthquake that occurred near Maule, Chile caused major damages to several piers in the Port of Coronel located approximately 160 kilometers (100 miles) to the South of the earthquake epicenter. One of the piers, the North Pier, experienced significant lateral spreading that was caused from liquefaction of the soils at the approach zone of the pier. Damages from lateral spreading and liquefaction effects consisted of sheet pile welding ruptures of the cross-support beams, stiffener buckling, pile displacements, pile rotations, and pier deck displacement. Researchers analyzed the North Pier after the earthquake and documented in detail …


Dynamic Cone Penetration Tests For Liquefaction Evaluation Of Gravelly Soils, Michael H. Talbot Aug 2018

Dynamic Cone Penetration Tests For Liquefaction Evaluation Of Gravelly Soils, Michael H. Talbot

Theses and Dissertations

Dynamic Cone Penetration Tests for LiquefactionEvaluation of Gravelly SoilsMichael H. TalbotDepartment of Civil and Environmental Engineering, BYUDoctor of PhilosophyIn North American practice, the Becker Penetration Test (BPT) has become the primary field test used to measure penetration resistance of gravelly soils. However, this test is expensive and uncertainties exist regarding correlations and corrections for rod friction. As an alternative, the dynamic penetration test (DPT) developed in China has recently been correlated with liquefaction resistance in gravelly soils. The DPT equipment consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of …


Reliability Of Feqdrain For Modeling Performance Of Sand Treated With Large-Diameter Prefabricated Drains For Liquefaction Mitigation, Travis Hatch Meservy Dec 2017

Reliability Of Feqdrain For Modeling Performance Of Sand Treated With Large-Diameter Prefabricated Drains For Liquefaction Mitigation, Travis Hatch Meservy

Theses and Dissertations

Finite element modeling of laminar shear box testing that consisted of loose sand treated with large diameter prefabricated vertical drains (PVDs), was performed. The objective of the modeling was to evaluate the reliability of the computer program FEQDrain for predicting excess pore pressure ratios (Ru) at sites treated with prefabricated drains. FEQDrain was found to be capable of successfully modeling measured excess pore pressure ratio time histories from the laminar shear box experiment, as long as an appropriate combination of €˜number of equivalent cycles and €˜shaking duration was chosen, and sensitive parameters were in the range of measured values. Hydraulic …


Reliability Of Feqdrain For Modeling Performance Of Sand Treated With Large-Diameter Prefabricated Drains For Liquefaction Mitigation, Travis Hatch Meservy Dec 2017

Reliability Of Feqdrain For Modeling Performance Of Sand Treated With Large-Diameter Prefabricated Drains For Liquefaction Mitigation, Travis Hatch Meservy

Theses and Dissertations

Finite element modeling of laminar shear box testing that consisted of loose sand treated with large diameter prefabricated vertical drains (PVDs), was performed. The objective of the modeling was to evaluate the reliability of the computer program FEQDrain for predicting excess pore pressure ratios (Ru) at sites treated with prefabricated drains. FEQDrain was found to be capable of successfully modeling measured excess pore pressure ratio time histories from the laminar shear box experiment, as long as an appropriate combination of ˜number of equivalent cycles and ˜shaking duration was chosen, and sensitive parameters were in the range of measured values. Hydraulic …


Development Of A Performance-Based Procedure For Assessment Of Liquefaction-Induced Lateral Spread Displacements Using The Cone Penetration Test, Tyler Blaine Coutu Oct 2017

Development Of A Performance-Based Procedure For Assessment Of Liquefaction-Induced Lateral Spread Displacements Using The Cone Penetration Test, Tyler Blaine Coutu

Theses and Dissertations

Liquefaction-induced lateral spread displacements cause severe damage to infrastructure, resulting in large economic losses in affected regions. Predicting lateral spread displacements is an important aspect in any seismic analysis and design, and many different methods have been developed to accurately estimate these displacements. However, the inherent uncertainty in predicting seismic events, including the extent of liquefaction and its effects, makes it difficult to accurately estimate lateral spread displacements. Current conventional methods of predicting lateral spread displacements do not completely account for uncertainty, unlike a performance-based earthquake engineering (PBEE) approach that accounts for the all inherent uncertainty in seismic design. The …


Development Of A Performance-Based Procedure For Assessment Of Liquefaction-Induced Lateral Spread Displacements Using The Cone Penetration Test, Tyler Blaine Coutu Oct 2017

Development Of A Performance-Based Procedure For Assessment Of Liquefaction-Induced Lateral Spread Displacements Using The Cone Penetration Test, Tyler Blaine Coutu

Theses and Dissertations

Liquefaction-induced lateral spread displacements cause severe damage to infrastructure, resulting in large economic losses in affected regions. Predicting lateral spread displacements is an important aspect in any seismic analysis and design, and many different methods have been developed to accurately estimate these displacements. However, the inherent uncertainty in predicting seismic events, including the extent of liquefaction and its effects, makes it difficult to accurately estimate lateral spread displacements. Current conventional methods of predicting lateral spread displacements do not completely account for uncertainty, unlike a performance-based earthquake engineering (PBEE) approach that accounts for the all inherent uncertainty in seismic design. The …


Performance-Based Liquefaction Triggering Analyses With Two Liquefaction Models Using The Cone Penetration Test, Alex Michael Arndt Aug 2017

Performance-Based Liquefaction Triggering Analyses With Two Liquefaction Models Using The Cone Penetration Test, Alex Michael Arndt

Theses and Dissertations

This study examines the use of performance-based engineering in earthquake liquefaction hazard analysis with Cone Penetration Test data (CPT). This work builds upon previous research involving performance-based liquefaction analysis with the Standard Penetration Test (SPT). Two new performance-based liquefaction triggering models are presented herein. The two models used in this liquefaction analysis are modified from the case-history based probabilistic models proposed by Ku et al. (2012) and Boulanger and Idriss (2014). Using these models, a comparison is made between the performance-based method and the conventional pseudo-probabilistic method. This comparison uses the 2014 USGS probabilistic seismic hazard models for both methods. …


Development Of A Simplified Performance-Based Procedure For The Assessment Of Liquefaction-Induced Settlements Using Liquefaction Loading Maps, Braden Michael Error Jul 2017

Development Of A Simplified Performance-Based Procedure For The Assessment Of Liquefaction-Induced Settlements Using Liquefaction Loading Maps, Braden Michael Error

Theses and Dissertations

This thesis derives the equations needed to perform a simplified analysis. The simplified procedure presented herein is then validated in which 15 cities across the United States are analyzed using both the simplified procedure and the full performance-based procedure. The simplified procedure is shown to adequately estimate a full performance-based procedure for post-liquefaction settlement. This thesis also presents SPLIQ, a spreadsheet tool that streamlines the derived simplified procedure in a single, user-friendly program. In an attempt to make performance-based engineering methods more accessible to engineers for routine projects, this thesis derives a simplified map-based procedure to evaluating performance-based post-liquefaction settlements. …


Development Of A Simplified Performance-Based Procedure For The Assessment Of Liquefaction-Induced Settlements Using Liquefaction Loading Maps, Braden Michael Error Jul 2017

Development Of A Simplified Performance-Based Procedure For The Assessment Of Liquefaction-Induced Settlements Using Liquefaction Loading Maps, Braden Michael Error

Theses and Dissertations

Liquefaction-induced settlement can cause extensive damage to infrastructure. Quantifying the amount of settlement that may occur after an earthquake is crucial to seismic design. The Pacific Earthquake Engineering Research (PEER) Center developed performance-based earthquake engineering (PBEE) as a probabilistic framework to characterize the risks associated with a seismic event. When applied to liquefaction-induced settlement, the PBEE framework provides a more complete and accurate representation of liquefaction hazard than other more conventional evaluation methods. Performance-based engineering is not widely used in practice, however, due to its complexity. In an attempt to make performance-based engineering methods more accessible to engineers for routine …


Full-Scale Testing Of Blast-Induced Liquefaction Downdrag On Driven Piles In Sand, Luke Ian Kevan Jul 2017

Full-Scale Testing Of Blast-Induced Liquefaction Downdrag On Driven Piles In Sand, Luke Ian Kevan

Theses and Dissertations

Deep foundations such as driven piles are often used to bypass liquefiable layers of soil and bear on more competent strata. When liquefaction occurs, the skin friction around the deep foundation goes to zero in the liquefiable layer. As the pore pressures dissipate, the soil settles. As the soil settles, negative skin friction develops owing to the downward movement of the soil surrounding the pile. To investigate the magnitude of the skin friction along the shaft three driven piles, an H-pile, a closed end pipe pile, and a concrete square pile, were instrumented and used to measure soil induced load …


Development Of A Performance-Based Procedure To Predict Liquefaction-Induced Free-Field Settlements For The Cone Penetration Test, Mikayla Son Hatch Jun 2017

Development Of A Performance-Based Procedure To Predict Liquefaction-Induced Free-Field Settlements For The Cone Penetration Test, Mikayla Son Hatch

Theses and Dissertations

Liquefaction-induced settlements can cause a large economic toll on a region, from severe infrastructural damage, after an earthquake occurs. The ability to predict, and design for, these settlements is crucial to prevent extensive damage. However, the inherent uncertainty involved in predicting seismic events and hazards makes calculating accurate settlement estimations difficult. Currently there are several seismic hazard analysis methods, however, the performance-based earthquake engineering (PBEE) method is becoming the most promising. The PBEE framework was presented by the Pacific Earthquake Engineering Research (PEER) Center. The PEER PBEE framework is a more comprehensive seismic analysis than any past seismic hazard analysis …


Development Of A Performance-Based Procedure For Assessment Of Liquefaction-Induced Free-Field Settlements, Brian David Peterson Dec 2016

Development Of A Performance-Based Procedure For Assessment Of Liquefaction-Induced Free-Field Settlements, Brian David Peterson

Theses and Dissertations

Liquefaction-induced settlement can cause significant damage to structures and infrastructure in the wake of a seismic event. Predicting settlement is an essential component of a comprehensive seismic design. The inherent uncertainty associated with seismic events makes the accurate prediction of settlement difficult. While several methods of assessing seismic hazards exist, perhaps the most promising is performance-based earthquake engineering, a framework presented by the Pacific Earthquake Engineering Research (PEER) Center. The PEER framework incorporates probability theory to generate a comprehensive seismic hazard analysis. Two settlement estimation methods are incorporated into the PEER framework to create a fully probabilistic settlement estimation procedure. …


Shaking Table Testing To Evaluate Effectiveness Of Prefabricated Vertical Drains For Liquefaction Mitigation, Caleb Robert Oakes Dec 2015

Shaking Table Testing To Evaluate Effectiveness Of Prefabricated Vertical Drains For Liquefaction Mitigation, Caleb Robert Oakes

Theses and Dissertations

This study was designed to evaluate the ability of vertical drains to prevent liquefaction and limit associated settlement. Drain performance was investigated using full-scale tests with vertical drains in liquefiable sand using a laminar shear box with acceleration time histories applied at the base. Performance of the sand box with drains in these tests was compared with performance of the sane box without drains in previous tests. The test data was also used to create case histories which can be used for further research and calibration of computer models. Although some investigations regarding vertical drains have been performed with centrifuge …


Development Of A Simplified Performance-Based Procedure For Assessment Of Liquefaction Triggering Using Liquefaction Loading Maps, Kristin Jane Ulmer Jul 2015

Development Of A Simplified Performance-Based Procedure For Assessment Of Liquefaction Triggering Using Liquefaction Loading Maps, Kristin Jane Ulmer

Theses and Dissertations

Seismically-induced liquefaction has been the cause of significant damage to infrastructure and is a serious concern in current civil engineering practice. Several methods are available for assessing the risk of liquefaction at a given site, each with its own strengths and limitations. One probabilistic method has been shown to provide more consistent estimates of liquefaction risk and can be tailored to the specific needs of a given project through hazard-targeted (i.e. based on return periods or likelihoods) results. This type of liquefaction assessment is typically called “performance-based,” after the Pacific Earthquake Engineering Research (PEER) Center's performance-based earthquake engineering framework. Unfortunately, …


Evaluation Of Empirical Prediction Methods For Liquefaction-Induced Lateral Spread From The 2010 Maule, Chile, MW 8.8 Earthquake In Port Coronel, Nicole D. Williams Jul 2015

Evaluation Of Empirical Prediction Methods For Liquefaction-Induced Lateral Spread From The 2010 Maule, Chile, MW 8.8 Earthquake In Port Coronel, Nicole D. Williams

Theses and Dissertations

Over the past several decades, empirical formulas have been developed and improved to predict liquefaction and lateral spread based on a database of case histories from observed earthquakes, such as Youd et al. (2002) and Rauch and Martin (2000). The 2010 Maule Chile earthquake is unique first of all because it is recent and was not used to develop recent liquefaction and lateral spread evaluation methods, and therefore can be reasonably used to evaluate the effectiveness of such equations. Additionally, the 8.8 magnitude megathrust event fills a significant gap in the databases used to develop these empirical formulas, which tends …


A Simplified Performance-Based Procedure For The Prediction Of Lateral Spread Displacements, Levi Thomas Ekstrom Jun 2015

A Simplified Performance-Based Procedure For The Prediction Of Lateral Spread Displacements, Levi Thomas Ekstrom

Theses and Dissertations

Characterization of the seismic hazard and ground-failure hazard of a site using traditional empirical lateral spread displacement models requires consideration of uncertainties in seismic loading, site conditions, and model prediction. Researchers have developed performance-based design methods to simultaneously account for these sources of uncertainty through the incorporation of a probabilistic analytical framework. While these methods can effectively handle the various sources of uncertainty associated with empirical lateral spread displacement prediction, they can be difficult for engineers to perform in a practical manner without the use of specialized numerical tools. To make the benefits of a performance-based approach accessible to a …


Evaluation Of Current Empirical Methods For Predicting Lateral Spread-Induced Ground Deformations For Large Magnitude Earthquakes Using Maule Chile 2010 Case Histories, Ginger Emily Tryon Dec 2014

Evaluation Of Current Empirical Methods For Predicting Lateral Spread-Induced Ground Deformations For Large Magnitude Earthquakes Using Maule Chile 2010 Case Histories, Ginger Emily Tryon

Theses and Dissertations

Improving seismic hazard analysis is an important part of building safer structures and protecting lives. Since large magnitude earthquakes are rarer than other earthquakes, it is harder to model seismic hazards such as lateral spread displacements for these events. Engineers are often required to extrapolate current lateral spreading models when designing utilities, bridges, and piers to withstand the ground displacements caused by earthquakes with magnitudes larger than 8.0. This study uses three case histories from the Maule Chile 2010 earthquake (Mw =8.8) to develop recommendations on which models are most accurate for large earthquake events and how to improve the …


Full-Scale Testing Of Blast-Induced Liquefaction Downdrag On Auger-Cast Piles In Sand, Joseph Erick Hollenbaugh Dec 2014

Full-Scale Testing Of Blast-Induced Liquefaction Downdrag On Auger-Cast Piles In Sand, Joseph Erick Hollenbaugh

Theses and Dissertations

Deep foundations like auger-cast piles and drilled shafts frequently extend through liquefiable sand layers and bear on non-liquefiable layers at depth. When liquefaction occurs, the skin friction on the shaft decreases to zero, and then increases again as the pore water pressure dissipates and the layer begins to settle, or compact. As the effective stress increases and the liquefiable layer settles, along with the overlaying layers, negative skin from the soil acts on the shaft. To investigate the loss of skin friction and the development of negative skin friction, soil-induced load was measured in three instrumented, full-scale auger-cast piles after …


Comparison Of Performance-Based Liquefaction Initiation Analyses Between Multiple Probabilistic Liquefaction Models Using The Standard Penetration Test, Alexander David Wright Jun 2013

Comparison Of Performance-Based Liquefaction Initiation Analyses Between Multiple Probabilistic Liquefaction Models Using The Standard Penetration Test, Alexander David Wright

Theses and Dissertations

For the most recent and correct article, please click here: http://ascelibrary.org/doi/abs/10.1061/9780784412787.086

This study examines the use of performance-based approaches in liquefaction hazard analysis. Two new methods of performance-based liquefaction initiation analysis are proposed which use the works of Juang et al. (2012) and Boulanger and Idriss (2012). Further advances are made by incorporating the performance-based magnitude scaling factors as proposed by Cetin et al. (2012). Using these new equations a comparative study is made between the three methods. Further comparisons are made between the performance-based approaches and the more widely used deterministic approaches. The comparisons reveal that on average for …


A Performance-Based Model For The Computation Of Kinematic Pile Response Due To Lateral Spreading And Its Application On Select Bridges Damaged During The M7.6 Earthquake In The Limon Province, Costa Rica, Kevin W. Franke Dec 2011

A Performance-Based Model For The Computation Of Kinematic Pile Response Due To Lateral Spreading And Its Application On Select Bridges Damaged During The M7.6 Earthquake In The Limon Province, Costa Rica, Kevin W. Franke

Theses and Dissertations

Lateral spread is a seismic hazard associated with soil liquefaction in which permanent deformations are developed within the soil profile due to cyclic mobility. Lateral spread has historically been one of the largest causes of earthquake-related damage to infrastructure. One of the infrastructure components most at risk from lateral spread is that of deep foundations. Because performance-based engineering is increasingly becoming adopted in earthquake engineering practice, it would be beneficial for engineers and researchers to have a performance-based methodology for computing pile performance during a lateral spread event. This study utilizes the probabilistic performance-based framework developed by the Pacific Earthquake …


Liquefaction Mitigation In Silty Sands Using Stone Columns With Wick Drains, Michael James Quimby Aug 2009

Liquefaction Mitigation In Silty Sands Using Stone Columns With Wick Drains, Michael James Quimby

Theses and Dissertations

Stone column treatment is commonly used to mitigate liquefaction hazard in sandy soils. Research and experience indicate that this method is effective for clean sands but that it may not be effective for silts and sands with fines contents greater than 15-20%. An alternative to the stone column method involves supplementing stone column treatment with pre-fabricated vertical wick drains installed prior to the stone columns installation. Although this method is used in practice, there has not been a formal academic study of its effectiveness. This thesis evaluates seven different case histories where wick drains were used and one where wick …


Liquefaction Mitigation Using Vertical Composite Drains And Liquefaction Induced Downdrag On Piles: Implications For Deep Foundation Design, Spencer R. Strand Mar 2008

Liquefaction Mitigation Using Vertical Composite Drains And Liquefaction Induced Downdrag On Piles: Implications For Deep Foundation Design, Spencer R. Strand

Theses and Dissertations

Deep foundations constructed in liquefiable soils require specialized design. The design engineer of such foundations must consider the effects of liquefaction on the foundation and overlying structure, such as excessive settlement, loss of skin friction at the soil-pile interface, and the development of downdrag on the pile. Controlled blasting was employed to liquefy a loose, saturated sand in order to test the liquefaction prevention capabilities of full-scale, vertical composite earthquake (EQ) drains and to investigate the development of downdrag on full-scale test piles. Blasting produced liquefaction at a test site without EQ drains which eventually resulted in 270 mm of …


Shear Modulus Degradation Of Liquefying Sand: Quantification And Modeling, Peter A. Olsen Nov 2007

Shear Modulus Degradation Of Liquefying Sand: Quantification And Modeling, Peter A. Olsen

Theses and Dissertations

A major concern for geotechnical engineers is the ability to predict how a soil will react to large ground motions produced by earthquakes. Of all the different types of soil, liquefiable soils present some of the greatest challenges. The ability to quantify the degradation of a soil's shear modulus as it undergoes liquefaction would help engineers design more reliably and economically. This thesis uses ground motions recorded by an array of downhole accelerometers on Port Island, Japan, during the 1995 Kobe Earthquake, to quantify the shear modulus of sand as it liquefies. It has been shown that the shear modulus …