Enhanced Integration of Shear Wave Velocity Profiling in Direct-Push Site Characterization Systems Alexander V. McGillivray 370 Pages Directed by Dr. Paul W. Mayne Shear wave velocity (VS) is a fundamental property of soils directly related to the shear stiffness at small-strains. Therefore, VS should be a routine measurement made during everyday site characterization. There are several lab and field methods for measuring VS, but the seismic piezocone penetration test (SCPTu) and the seismic dilatometer test (SDMT) are the most efficient means for profiling the small-strain stiffness in addition to evaluating large-strain strength, as well as providing evaluations of the geostratigraphy, stress state, and permeability, all within a single sounding. Although the CPT and DMT have been in use for over three decades in the USA, they are only recently becoming commonplace on small-, medium-, and large-size projects as more organizations begin to realize their benefits. Regrettably, the SCPTu and the SDMT are lagging slightly behind their non-seismic counterparts in popularity, in part because the geophysics component of the tests has not been updated during the 25 years since the tests were envisioned. The VS measurement component is inefficient and not cost effective for routine use. The purpose of this research is to remove the barriers to seismic testing during direct-push site characterization with SCPTu and SDMT. A continuous-push seismic system has been developed to improve the integration of VS measurements with SCPTu and SDMT, allowing VS to be measured during penetration without stopping the progress of the probe. A new type of portable automated seismic source, given the name RotoSeis, was created to generate repeated hammer strikes at regularly spaced time intervals. A true-interval biaxial seismic probe and an automated data acquisition system were also developed to capture the shear waves. By not limiting VS measurement to pauses in penetration during rod breaks, it is possible to make overlapping VS interval measurements. This new method, termed frequent-interval, increases the depth resolution of the VS profile to be more compatible with the depth intervals of the near-continuous non-seismic measurements of the SCPTu and the SDMT.

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 PBEE approach incorporates complex probability theory throughout all aspects of estimating liquefaction-induced lateral spread displacements. A new fully-probabilistic PBEE method, based on results from the cone penetration test (CPT), was created for estimating lateral spread displacements using two different liquefaction triggering procedures. To accommodate the complexity of all probabilistic calculations, a new seismic hazard analysis tool, CPTLiquefY, was developed. Calculated lateral spread displacements using the new fully-probabilistic method were compared to estimated displacements using conventional methods. These comparisons were performed across 20 different CPT profiles and 10 cities of varying seismicity. The results of this comparison show that the conventional procedures of estimating lateral spread displacements are sufficient for areas of low seismicity and for lower return periods. However, by not accounting for all uncertainties, the conventional methods under-predict lateral spread displacements in areas of higher seismicity. This is cause for concern as it indicates that engineers in industry using the conventional methods are likely under-designing structures to resist lateral spread displacements for larger seismic events.

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 PBEE approach incorporates complex probability theory throughout all aspects of estimating liquefaction-induced lateral spread displacements. A new fully-probabilistic PBEE method, based on results from the cone penetration test (CPT), was created for estimating lateral spread displacements using two different liquefaction triggering procedures. To accommodate the complexity of all probabilistic calculations, a new seismic hazard analysis tool, CPTLiquefY, was developed. Calculated lateral spread displacements using the new fully-probabilistic method were compared to estimated displacements using conventional methods. These comparisons were performed across 20 different CPT profiles and 10 cities of varying seismicity. The results of this comparison show that the conventional procedures of estimating lateral spread displacements are sufficient for areas of low seismicity and for lower return periods. However, by not accounting for all uncertainties, the conventional methods under-predict lateral spread displacements in areas of higher seismicity. This is cause for concern as it indicates that engineers in industry using the conventional methods are likely under-designing structures to resist lateral spread displacements for larger seismic events.

Cone penetration in sands is a complex process: it contains several challenges that geomechanicians face, such as large displacements, large strains, strain localization, and microscale phenomena such as particle crushing and sand fabric evolution. In order to gain a deeper understanding of the penetration process and the mechanisms controlling penetration resistance, capturing these displacement and strain fields and microscale phenomena is necessary. Furthermore, as more sophisticated theoretical models become available for the simulation of the cone penetration problem, the experimental validation of those methods becomes vital.<br><div><br></div><div>This dissertation presents a multiscale study of the cone penetration process in silica sands. The penetration problem is investigated using a combinational approach consisting of calibration chamber experiments, digital image correlation (DIC) analysis, and X-ray computed Tomography (XCT) scans. Three silica sands with different particle characteristics are used in the experimental program. These three sands have similar particle size distributions; however, they differ in particle morphologies and particle strengths. These differences allow a study of the effect of microscale sand properties on the macroscale response of the sands to the cone penetration process. The three silica sands used in this research are fully characterized using laboratory experiments to obtain particle size distributions, particle morphologies, particle crushing strengths, minimum and maximum packing densities, and critical-state friction angles. Subsequently, both dense and medium-dense samples of the three sands are compressed in a uniaxial loading device placed inside an X-ray microscope (XRM) and scanned at multiple stress levels during uniaxial compression. Results from uniaxial compression experiments indicate that: (1) the compressibility of the sands is closely tied to particle morphology and strength, and (2) the anisotropy in the orientations of interparticle contact normals generally increases with axial stress; however, this increase is limited by the occurrence of particle crushing in the sample.<br></div><div><br></div><div>Subsequently, cone penetration experiments are performed under different confinement levels on dense samples of the three sands in aspecial half-cylindrical calibration chamber equipped with DIC capabilities. For each penetration experiment, incremental displacement fields around the cone penetrometer are obtained using DIC analysis, and these incremental displacement fields are further analyzed to compute the incremental strain fields. A novel methodology is developed to obtain the shear-band patterns that develop around the penetrometer automatically. Furthermore, differences in the shear-band patterns in deep and shallow penetration environments are also investigated. Results show that strain fields tend to localize intensely near the penetrometer tip, and the shear bands tend to develop along the inclined face and near the shoulder of the penetrometer. Significant differences in the shear band patterns in deep and shallow penetration environments are also observed.<br></div><div><br></div><div>After each cone penetration experiment, a specially developed agar-impregnation technique is used to collect minimally disturbedsand samples from around the penetrometertip. These agar-impregnated sand samples are scanned in the XRM to obtain 3D tomography data, which are further analyzed to quantify particle crushing around the penetrometer tip. The results show that: (1) for a given sample density, the amount of crushing around the cone penetrometer depends on the confinement and the sand particle characteristics, (2) the level of crushing is not uniform around the penetrometer tip, with more severe crushing observed near the shoulder of the penetrometer, and (3) the regions with more severe particle crushing around the penetrometer approximately overlap with regions of high shear strain and volumetric contraction. A framework is also proposed to obtain the ratio of penetration resistance in more crushable sands to penetration resistance in less crushable sands. Furthermore, a novel resin-impregnation technique is also developed to collect undisturbedsand samples from around the penetrometer tip. The resin-impregnated sand sample collected after one of the penetration experiments is scanned in the XRM to obtain the 3D tomography data, which is then analyzed to obtain the distribution of interparticle contact normal orientations at multiple locations around the penetrometer tip. These analyses indicate that the interparticle contact normals tend to orient themselves with the incremental principal strains around the penetrometer: below the penetrometer tip, the interparticle contact normals orient vertically upwards, while closer to the shoulder of the penetrometer, the interparticle contact normals become more radially inclined.<br></div><div><br></div><div>Data presented in this dissertation on penetration resistance, incremental displacement fields, incremental strain fields, particle crushing, and interparticle contact normal orientations around the cone penetrometer are aimed to be useful to researchers working on the multiscale modeling of penetration processes in granular materials and aid in the further development of our understanding of penetration processes in sands.<br></div>

The object of the thesis is soils that occur within the territory of Lithuania and may be used as basis for building foundations. The thesis studies the interpretation of the results of Dynamic Penetration Test (DPT) and Cone Penetration Test (CPT) of soils, reliability of direct (number of blows (Nx)) and de-rivative (dynamic point resistance (qd)) DPT parameters, analyses the result influencing factors and interrelation between DPT and CPT parameters. The data analysis has been performed by means of mathematical methods of statistics, also using analytical and empirical solutions. Having examined calculation data it was determined that the indirect parameter of Dy-namic Penetration Test – dynamic point resistance (qd) should not be used due to calculation de-faults and replaced with the direct parameter – number of blows (Nx). The analysis of DPT re-sults influencing factors shows that the lateral overburden pressure together with friction of rods are those with the greatest impact on penetration data. Within the scope of the work, it has re-vealed that the number of blows (Nx) and static cone resistance (qc) are closely correlated and it depends on the grain size distribution of soil, geotechnical properties and depth of occurrence. / Disertacijos objektas yra Lietuvos teritorijoje slūgsantys gruntai, kurie gali būti statinių pamatų pagrindu. Disertacijoje nagrinėjama grunto tyrimo dinaminiu (DPT) ir statiniu (CPT) zondavimu rezultatų interpretacija, tiesioginio (smūgių skaičiaus (Nx)) ir išvestinio (dinaminės kūgio smigos (qd)) DPT rodiklių patikimumas, analizuojami rezultatus įtakojantys veiksniai ir sąsajos tarp DPT bei CPT zondavimo rodiklių. Duomenų analizė atlikta matematiniais statistiniais metodais, taip pat panaudojant analitinius ir empirinius sprendinius. Išnagrinėjus skaičiavimo duomenis buvo nustatyta, kad netiesioginis dinaminio zonda-vimo rodiklis – dinaminė kūgio smiga (qd) dėl skaičiavimo trukumų yra nenaudotinas ir keisti-nas į tiesioginį rodiklį – smūgių skaičių (Nx). DPT rezultatus įtakojančių veiksnių analizė paro-dė, kad zondavimo duomenims didžiausią įtaką turi gruntų šoninis geostatinis slėgis ir kartu zondavimo štangų trintis į gruntą. Darbo metu buvo gauta, kad egzistuoja tamprus koreliacinis ryšys tarp smūgių skaičiaus (Nx) ir statinės kūgio spraudos (qc), kuris priklauso nuo grunto gra-nuliometrinės sudėties, mechaninių savybių ir slūgsojimo gylio.

Disertacijos objektas yra Lietuvos teritorijoje slūgsantys gruntai, kurie gali būti statinių pamatų pagrindu. Disertacijoje nagrinėjama grunto tyrimo dinaminiu (DPT) ir statiniu (CPT) zondavimu rezultatų interpretacija, tiesioginio (smūgių skaičiaus (Nx)) ir išvestinio (dinaminės kūgio smigos (qd)) DPT rodiklių patikimumas, analizuojami rezultatus įtakojantys veiksniai ir sąsajos tarp DPT bei CPT zondavimo rodiklių. Duomenų analizė atlikta matematiniais statistiniais metodais, taip pat panaudojant analitinius ir empirinius sprendinius. Išnagrinėjus skaičiavimo duomenis buvo nustatyta, kad netiesioginis dinaminio zonda-vimo rodiklis – dinaminė kūgio smiga (qd) dėl skaičiavimo trukumų yra nenaudotinas ir keisti-nas į tiesioginį rodiklį – smūgių skaičių (Nx). DPT rezultatus įtakojančių veiksnių analizė paro-dė, kad zondavimo duomenims didžiausią įtaką turi gruntų šoninis geostatinis slėgis ir kartu zondavimo štangų trintis į gruntą. Darbo metu buvo gauta, kad egzistuoja tamprus koreliacinis ryšys tarp smūgių skaičiaus (Nx) ir statinės kūgio spraudos (qc), kuris priklauso nuo grunto gra-nuliometrinės sudėties, mechaninių savybių ir slūgsojimo gylio. / The object of the thesis is soils that occur within the territory of Lithuania and may be used as basis for building foundations. The thesis studies the interpretation of the results of Dynamic Penetration Test (DPT) and Cone Penetration Test (CPT) of soils, reliability of direct (number of blows (Nx)) and de-rivative (dynamic point resistance (qd)) DPT parameters, analyses the result influencing factors and interrelation between DPT and CPT parameters. The data analysis has been performed by means of mathematical methods of statistics, also using analytical and empirical solutions. Having examined calculation data it was determined that the indirect parameter of Dy-namic Penetration Test – dynamic point resistance (qd) should not be used due to calculation de-faults and replaced with the direct parameter – number of blows (Nx). The analysis of DPT re-sults influencing factors shows that the lateral overburden pressure together with friction of rods are those with the greatest impact on penetration data. Within the scope of the work, it has re-vealed that the number of blows (Nx) and static cone resistance (qc) are closely correlated and it depends on the grain size distribution of soil, geotechnical properties and depth of occurrence.

Portrycket är en viktig parameter för att bestämma jordens egenskaper, såsom dränering, permeabilitet och stabilitet (då portrycket har en påverkan på den effektiva spänningen i jorden). Portrycket kan mätas med portrycksmätare men det kan även mätas under ett Cone penetrating test (CPT) med ett s.k. dissipationstest. Fördelar med ett dissipationstest jämfört med traditionell portrycksmätning skulle vara att det skulle spara tid och pengar, då man slipper trycka ner portrycksmätare och sedan vänta på att få portrycket ifrån dem, istället kan portrycket mätas under sondering med CPT.Detta självständiga arbete har som syfte att jämföra portrycksmätningar mellan portrycksmätning med BAT-spets och dissipationstest under CPT-sondering för att se hur bra mätvärden dissipationstester ger och om de eventuellt kan ersätta portrycksmätare. Fältförsöken av metoderna skedde i Uppsalalera, på en tomt i Kungsängen i Uppsala.Två stationer med BAT-spetsar på 5 meter, 7,5 meter och 10 meters djup sattes ner i leran. Sondering med CPT genomfördes sedan, där borren stoppades på samma djup som BAT-spetsarna. CPT:n stoppades på dessa djup i drygt 24 timmar, för att tillåta det generade portrycket som skapades när borren trycks ner i leran att skingras åt sidan. Jämviktsportrycket kommer vara det portryck som finns kvar efter att det generade portrycket har försvunnit. Portrycken från de två olika metoderna jämfördes sedan för att se hur nära dissipationstestet kommer värdena från portrycksmätningen med BAT-spetsarna.Resultatet av dissipationstesterna blev att inga av dem nådde referensvärdena från BAT-spetsarna efter 24 timmar. Beroende på användningsklass ligger dissipationstesterna inom den tillåtna minsta noggrannheten. Dissipationstest är antagligen inte så praktiskt tillämpbart i jordar med låg permeabilitet. / The pore pressure is an important parameter for determining the properties of thesoil, such as drainage, permeability and stability (since the pore pressure has aneffect on the effective stress in the soil). The pore pressure can be measured withpore pressure gauges but it can also be measured during a Cone penetration test(CPT) with a dissipation test. Advantages of a dissipation test compared tomeasurement with traditional pore pressure gauges would be that it would save timeand money, since you don’t have to press down pore pressure gauges and then waitto get the pore pressure from them, instead the pore pressure can be measuredduring probing with CPT.The purpose of this project is to compare pore pressure measurements betweenpore pressure measurements with BAT-tips and dissipation test during CPT probing,to see how good measured values the dissipation tests will provide and if theyeventually can supersede pore pressure gauges for pore pressure measurements.The field tests of the methods were done in Uppsala clay, on a site in Kungsängen inUppsala.Two stations with BAT-tips at 5 meters, 7.5 meters and 10 meters depth wereinstalled in the clay. Probing with CPT was then carried out, by stopping the CPT atthe same depth as the BAT-tips. Measurements with the CPT were done at thesedepths for just over 24 hours, to allow the generated excess pore pressure createdwhen the cone is pushed into the clay to disperse to the sides. The equilibrium porepressure is the pore pressure that remains after the generated pore pressure hasdissipated. The pore pressure from the two different methods was then compared tosee how close the dissipation test results were to the values from the pore pressuremeasurements with the BAT tips.The result of the dissipation tests was that none of them reached the referencevalues from the BAT-tips after 24 hours. Depending on the chosen application class,the dissipation tests are within the permitted minimum accuracy. Dissipation tests areprobably not practically applicable to soils with low permeability.

One of the most critical problems geotechnical engineers face with is the determination of the amount of consolidation settlement that will occur at a site as a result of the construction of a structure. The compressibility behavior of the soil is an important parameter in determining the amount of consolidation settlement. The goal of this study is to develop probabilistically based correlation between the compressibility behavior of soil and in-situ test data. Within the scope of this research effort, performed CPT tests and the recorded settlement case histories where consolidation settlements at the field under various surcharge loads were compiled from the Bursa East and West Waste Water Treatment Plant soil investigation projects. A database was composed of the results of 45 CPT and 57 settlement plate recordings. For the compilation of this database, a series of finite difference software FLAC-3D analyses were carried out to calculate the change in stress distribution under the settlement plates. A maximum likelihood framework was used for the development of compressibility behavior of soils. As a result of careful processing of available data, the cone tip resistance (qc), soil behavior type index (Ic) were selected as two important parameters effecting the value of the one-dimensional constraint modulus, M. The regression analysis which uses the settlement values recorded at the site and those computed using the change in the stress distribution, the thickness of the sublayers and the proposed one-dimensional constraint modulus were carried out to calculate the values of these model parameters. Two correlations based on the cone tip resistance and soil behavior type index were developed for the computation of the one-dimensional constraint modulus, M.

A reflectometria no domínio do tempo permite estimar o teor de umidade de um meio através da sua correlação com a constante dielétrica. Uma sonda helicoidal TDR, que pode ser cravada em conjunto outros ensaios de penetração in situ para a estimativa do teor de umidade em diversas profundidades, tem aplicação interessante para a investigação geotécnica do subsolo. No presente trabalho, uma sonda TDR foi adaptada e utilizada em conjunto ao ensaio CPT para caracterização de um perfil de solo arenoso não saturado que ocorre na região de Bauru (SP). A calibração dessa sonda foi feita em laboratório especificamente para esse solo. As equações de calibração que mostraram os melhores resultados foram definidas correlacionando a constante dielétrica, condutividade elétrica aparente e a massa específica seca com o teor de umidade. Com o intuito de melhorar a acurácia na determinação do teor de umidade em campo e eliminar possíveis interferências no registro da onda eletromagnética, foram efetuadas modificações em algumas características do projeto original dessa sonda. Tais modificações consistiram em separar os eletrodos condutores e as partes metálicas da sonda, e eliminar o cabo coaxial de extensão, conectando a sonda diretamente a um cabo coaxial de 12 m de comprimento. Tais mudanças levaram a uma melhoria significativa na determinação do perfil de teor de umidade do local estudado. Os valores de teor de umidade de campo determinados usando o TDR ao longo de 8 m de profundidade foram comparados com os valores de referência obtidos de amostras deformadas retiradas com trado mecânico. O erro médio na estimativa do perfil de teor de umidade gravimétrico utilizando a sonda TDR helicoidal foi de 1.61%, na última campanha de ensaios realizados. Os resultados dessa pesquisa indicam que esta ferramenta é adequada para estimar do perfil de teor de umidade para uso em conjunto com o ensaio CPT. / The time domain reflectometry allows estimating the moisture content of a medium by means of its correlation with the dielectric constant. A coil TDR probe, which can be driven into the ground together with others in situ penetration tests, can be used to estimate the moisture content at different depths. It is an interesting approach for geotechnical site characterization. In this work, a coil TDR probe was adapted and used in combination with the CPT test for the site characterization of an unsaturated sandy soil profile which occurs in the region of Bauru (SP). The probe calibration was performed in laboratory specifically for that soil. The calibration equation, which presented the best results, were defined correlating the dielectric constant, electrical conductivity and dry density with the moisture content. In order to improve the accuracy for determining the water content in the field and to eliminate possible interference on the electromagnetic wave registration, modifications were made in some characteristics of the original design of this probe. Such modifications consisted in separating the conductive electrodes from the metal parts of the probe, and eliminating the coaxial extension cable, connecting the probe directly to a coaxial cable 12 m long. Such changes have led to a significant improvement in the determination of the moisture content profile of the studied site. The moisture content values determined in situ by using the TDR along 8 m depth were compared with reference values obtained from disturbed soil samples collected using mechanical augers. The root mean square error of the gravimetric water content profile using the TDR coil probe was 1.61% in the last test campaign. The results of this research indicate that this tool is suitable to estimate the gravimetric moisture content together with the CPT test.

The properties of natural soil are inherently variable and influence design decisions in geotechnical engineering. Apart from the inherent variability of the soil, the variability may arise due to measurement of soil properties in the field or laboratory tests and model errors. These wide ranges of variability in soil are expressed in terms of mean, variance and autocorrelation function using probability/reliability based models. The most common term used in reliability based design is the reliability index, which is a probabilistic measure of assurance of performance of structure. The main objective of the reliability based design is to quantify probability of failure/reliability of a geotechnical system considering variability in the design parameters and associated safety. In foundation design, reliability based design is useful compared to deterministic factor of safety approach. Several design codes of practice recommend the use of limit state design concept based on probabilistic models, and suggest that, development of reliability based design methodologies for practical use are of immense value. The objective of the present study is to propose reliability based design methodologies for pile foundations under static and seismic loads. The work presented in this dissertation is subdivided into two parts, namely design of pile foundations under static vertical and lateral loading; and design of piles under seismic loading, embedded in non-liquefiable and liquefiable soil. The significance of consideration of variability in soil parameters in the design of pile foundation is highlighted. A brief review of literature is presented in Chapter 2 on current pile design methods under vertical, lateral and seismic loads. It also identifies the scope of the work. Chapter 3 discusses the methods of analysis which are subsequently used for the present study. Chapter 4 presents the reliability based design methodology for vertically and laterally loaded piles based on cone penetration test data for cohesive soil. CPT data from Konaseema area in India is used for analysis. Ultimate limit sate and serviceability limit state are considered for reliability based design using CPT data and load displacement curves. Chapter 5 presents the load resistance factor design (LRFD) of vertically and laterally loaded piles based on load test data. Reliability based code calibrated partial factors are determined considering bias in failure criteria, model bias and variability in load and resistance. Chapter 6 illustrates a comprehensive study on the effect of soil spatial variability on response of vertically and laterally loaded pile foundations in undrained clay. Two-dimensional finite difference program, FLAC2D (Itasca 2005) is used to model the soil and pile. The response of pile foundations due to the effect of variance and spatial correlation of undrained shear strength is studied using Monte Carlo simulation. The influence of spatial variability on the propagation and formation of failure near the pile foundation is also examined. Chapter 7 describes reliability based design methodology of piles in non-liquefiable soil. The seismic load on pile foundation is determined from code specified elastic design response spectrum using pseudo-static approach. Variability in seismic load and soil undrained shear strength are incorporated. The effects of soil relative densities, pile diameters, earthquake predominant frequencies and peak acceleration values on the two plausible failure mechanisms; bending and buckling are examined in Chapter 8. The two-dimensional finite difference analysis is used for dynamic analysis. A probabilistic approach is proposed to identify governing failure modes of piles in liquefiable soil in Chapter 9. The variability in the soil parameters namely SPT-N value, friction angle, shear modulus, bulk modulus, permeability and shear strain at 50% of modulus ratio is considered. Monte Carlo simulation is used to determine the probability of failure. A well documented case of the failed pile of Showa Bridge in 1964 Niigata earthquake is considered as case example. Based on the studies reported in this dissertation, it can be concluded that the reliability based design of pile foundations considering variability and spatial correlation of soil enables a rational choice of design loads. The variability in the seismic design load and soil shear strength can quantify the risk involved for pile design in a rational basis. The identification of depth of liquefiable soil layer is found to be most important to identify failure mechanisms of piles in liquefiable soil. Considerations of soil type, earthquake intensity, predominant frequency of earthquake, pile material, variability of soil are also significant.