Many embankments on the soft, highly variable, recent alluvial deposits along the South African coast have suffered large settlements necessitating ongoing costly repairs. Due to the soft variable soils, borehole sampling is difficult and laboratory testing requires to be extensive for adequate subsoil modelling; cone penetration testing was considered to be a potential means to overcome these problems. Twenty five years ago in South Africa, as elsewhere, cone penetration testing equipment was relatively crude and the methods of interpretation were simplistic. The application of cone penetration testing to recent alluvial deposits therefore required improvements to both the equipment and the derivation of soil parameters. The equipment was upgraded by introducing strain gauge load cells capable of measuring cone pressures in soft clays with adequate accuracy. Hence, correlations of cone pressures with compressibility and shear strength became possible. Predictions of settlement times and magnitudes are of equal importance and a consolidometer-cone system was developed to assess both of these. A piezometer was incorporated into a cone to ascertain whether the settlements were due to consolidation. The piezometer cone performed so well that it superseded the consolidometer-cone and by 1977 a field piezometer cone was in regular use. Developments in piezocone interpretation have taken place concurrently with those in equipment; coefficients of consolidation are evaluated from pore pressure dissipations, and soils identified from the ratio of pore and cone pressures. These developments have been validated in two recent research projects, by comparing measured and predicted settlements at eleven embankments monitored for up to fifteen years. The data shows that for embankments on the recent alluvial deposits the constrained modulus coefficient, am is : am = 2,6 ± 0,6 The data also shows that coefficients of consolidation from piezometer cone dissipation tests are correlated with those from laboratory tests and back analysed embankment performance as follows : Embankment c = 3 CPTU c = 6 Lab cv It is concluded that piezometer cone penetration testing is particularly suitable for the geotechnical investigation and the subsequent design of embankments on recent alluvial deposits and should be considered as complementary to boreholes with sampling and laboratory testing. The existing database of embankment performance should be expanded with particular emphasis on long term measurements and on thorough initial determination of basic soil parameters / Thesis (Ph.D.)-University of Natal, Durban, 1992.

No description available.

Thesis (Ph. D.)--Carleton University, 2001. / Includes bibliographical references (p. 193-208). Also available in electronic format on the Internet.

Thesis (M.Eng.) -- Memorial University of Newfoundland. / Bibliography : leaves 118-122. Also available online.

Geotekniska undersökningar används för att få en uppfattning om markförhållanden. Ett exempel på en geoteknisk undersökningsmetod är standard penetration test (SPT). Denna metod kombinerar dynamisk sondering med provtagning och används för att kunna härleda bärförmåga i en jord. Metoden uppstod i början av 1900-talet och utrustningen korrigerades fram till 1930-talet. Sedan dess har utvecklingen av metoden i princip stått still. Det finns ingen internationell standard för SPT idag och metoden kan därför skilja sig i olika delar av världen. Sonderingen utförs i botten av ett förborrat borrhål med en öppen provtagare. Serier om maximalt 450 millimeter kan tas samtidigt och intervallet mellan serierna rekommenderas till 0,75–1,5 meter. SPT är en välanvänd metod internationellt sett, medan användandet i Sverige är begränsat. En av de mer frekvent använda dynamiska sonderingsmetoderna som används i Sverige är hejarsondering med frifallshejare och fast dyna (HfA). Metoden utvecklades från den traditionella hejarsonderingsmetoden under 1960-talet och sedan HfA standardiserades på 1970-talet har metoden knappt utvecklats. Idag finns metoden i den europeiska standarden under namnet DPSH-A med tillägg i en svensk bilaga. HfA använder sig av en konspets som slås ned av en fallande hammare. HfA kan användas om fasta jordlager söks men även för att härleda jordparametrar som friktionsvinkel och elasticitetsmodul. Syftet med rapporten är att se om metoderna SPT och HfA relaterar till varandra. Undersökningar med respektive metod har genomförts i fyra områden, Luleå hamn, Gammelstad, Aitik respektive Kristineberg. Avståndet mellan sonderingspunkterna för de två metoderna i Luleå hamn, Gammelstad och Kristineberg är ungefär en meter, medan avståndet i Aitik varierar mellan 10–30 meter. För att avgöra vilken jordart sonderingarna utförts i har okulär jordartsbedömning gjorts på provtagning från SPT för områdena Luleå hamn, Aitik och Kristineberg. För proverna från Gammelstad har siktningslaboration utförts. Rekommendationer för att korrigera uppmätt antal slag för SPT tar hänsyn till olika faktorer beroende på vart metoden geografiskt sett används. Enligt den europeiska standarden ska metoden korrigeras för energiförhållandet i testutrustningen, längden på borrstål samt vertikalspänning orsakat av överbelastning av jord. Housing and Building Research Institute rekommenderar att uppmätt antal slag även korrigeras för borrhålets diameter och provtagartyp. Enligt U.S. Department of Transportation ska antalet slag endast korrigeras för energiförhållandet i testutrustningen och för vertikalspänning orsakat av överbelastning av jord. För att beräkna friktionsvinkel utifrån SPT-resultat kan åtta ekvationer användas. Elastisitetsmodul kan beräknas med två ekvationer. För HfA rekommenderas en ekvation för korrigering, en för beräkning av friktionsvinkel och en för beräkning av elasticitetsmodul. Tidigare gjorda jämförelser tyder på att det kan finnas ett samband mellan metoderna. Även resultatet från denna rapport tyder på att det kan vara möjligt att hitta ett samband, även om metoderna skiljer sig i vissa lägen. Elasticitetsmodulen skiljer sig kraftigt mellan HfA och SPT, men även för de två ekvationerna som presenterats för SPT. Friktionsvinkeln för SPT ger en stor spridning och den beräknade friktionsvinkeln för HfA hamnar kring medelvärdet för SPT. / Geotechnical investigations are mainly used to get an idea the condition of the subsurface. An example of a geotechnical investigation method is the standard penetration test (SPT). This method combines dynamic sounding with sampling and can be used to deduce the bearing capacity of a soil. SPT was invented in the beginning of the 20:th century and corrections of the method was done until the 1930s. Since then, the development of the method has been at a standstill. Today there is no international standard for SPT, and the execution does therefore vary across the globe. SPT is performed with an open sampler at the bottom of a predrilled borehole. Series of a maximum of 450 millimeters can be taken at the same time and the interval between the series is recommended to 0,75-1,5 meters. SPT is commonly used internationally, but the usage of the method in Sweden is limited. A commonly used dynamic sounding method is the Swedish dynamic probing (HfA). This method was developed in the 1960s. The development of the method has been on a standstill since it was standardized in the 1970. Today, the method goes by the category DPSH-A supplemented by a Swedish appendix in the European standard. HfA uses a conical tip which is blown down by a falling hammer. HfA is used in the search for solid soil layers but can also be used to deduce soil parameters such as angle of friction and elasticity modulus. The aim with this master thesis is to determine if SPT and HfA relates to one another. Investigations has been performed in four areas, Luleå harbour, Gammelstad, Aitik and Kristineberg. The distance between the probing points for SPT and HfA at Luleå harbour, Gammelstad and Kristineberg is about one meter. The distance in Aitik varies between 10 to 30 meters. Ocular soil type assessment was performed for the soil samples in Luleå harbour, Aitik and Kristineberg and sieving was performed for the samples taken in Gammelstad. Recommendations for correction of the number of blows for SPT takes different factors into consideration depending on where the test is performed. According to the European standard, the energy efficiency of the equipment, length of the rods and the overburden pressure should be corrected for. Housing and Building Research Institute recommends adding on corrections for the borehole diameter and the type of sampler. Correction should only be done for the energy efficiency of the equipment and the overburden pressure according to U.S. Department of Transportation. There is a total of ten equations available to determine the angle of friction based on results from SPT, while there are two equations available to determine the elasticity modulus. On the other hand, there is only one equation for correction, one to determine angle of friction and one to determine the elasticity modulus for HfA. Previous comparisons of these two methods shows that there is a possibility to find a relation between the methods. The result from this report also indicates that there may be possible to find a relation between the methods, even if they do differ in some cases. The elasticity modulus does vary a lot between the two methods, but also between the two equations found for SPT. The angle of friction for SPT shows a large variation but the calculated angle of friction for HfA ends up around the mean value for the equations for SPT.

published_or_final_version / Applied Geosciences / Master / Master of Science

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy, 2016 / The performance in tailings storage facilities (TSFs) of three methods based on the cone penetration test (CPT) to assess liquefaction potential is explored. For two of these methods the investigation highlights potential limitations mostly related with the experimental data that supports some of the equations used by the methods. However, the methodologies yielded mostly correct performance predictions when implemented on TSF case histories in which an undrained response is believed to have occurred. The positive performance of both methodologies must be tempered by the limitations identified in the methods. The steady state line (SSL) is an input of the third method considered. Accordingly, the correlation between the SSL and soil index parameters was investigated using a database of 151 non-plastic soiltypes compiled from data previously reported in the literature. The SSLs were modelled in void ratio (e) - mean effective stress (p') space, using a logarithmic equation. The y-intercept of the SSL is termed Γ, and the slope is termed λ. A direct, and linear (R2 = 0.74) correlation between the minimum void ratio (emin) and Γ was found. Although previous research has explored the effect of non-plastic fines on the SSL, the analysis presented herein shows that the Γ-emin correlation is independent of fines content. The correlation is also independent of the angularity of the particles provided that these are bulky, as opposed to platy. A direct λ-emin correlation was also found; however this correlation is much weaker and probably obscured by uncertainties in void ratio measurements. Triaxial testing was conducted to determine the SSLs of three tailings soiltypes obtained from a single TSF. The trends observed in the resulting SSLs are in agreement with the Γ-emin and λ-emin correlations from the database. An assessment was made of the sensitivity of the third method, which is based on a state parameter (ψ), to variations in λ throughout a single TSF. It was found that in some TSFs, the variations of λ are small enough to be disregarded without significantly affecting the accuracy of ψ. However, in other TSFs it is necessary to estimate how λ varies throughout the deposit. iii / CK2017

Effect of cementitious stabilization on the stress-compressibility characteristics of three different South Florida organic soils were evaluated in this study. The objectives of the research were to (l) determine if the secondary compression characteristics of organic soils and peats can be stabilized with (a) cement only, (b) binary blends of cement/slag (C-S), cement/gypsum (C-G), and cement/cement-kiln-dust (C-CKD) and (c) ternary blend of cement-slag-gypsum in equal proportions; (ll) quantify the effectiveness of cementitious stabilization by evaluating the time-stress-compressibility (t-log σ'v - e) relationship in terms of the Cα / Cc ratio; and (lll) provide some guidelines for selecting optimum dosage of cementitious materials in deep mixing methods when organic soils and peats are encountered. It was concluded that cementitious mixes containing various waste materials is effective in controlling the secondary compression behavior of organic soils, and therefore should be considered in deep mixing methods as a sustainable practice. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Thesis. 1978. Sc.D.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 416-426. / Sc.D.

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 methods because it thoroughly incorporates probability theory into all aspects of post-liquefaction settlement estimation. One settlement estimation method, used with two liquefaction triggering methods, is incorporated into the PEER framework to create a new PBEE (i.e., fully-probabilistic) post-liquefaction estimation procedure for the cone penetration test (CPT). A seismic hazard analysis tool, called CPTLiquefY, was created for this study to perform the probabilistic calculations mentioned above. Liquefaction-induced settlement predictions are computed for current design methods and the created fully-probabilistic procedure for 20 CPT files at 10 cities of varying levels of seismicity. A comparison of these results indicate that conventional design methods are adequate for areas of low seismicity and low seismic events, but may significantly under-predict seismic hazard for areas and earthquake events of mid to high seismicity.