Este trabalho aborda uma análise comparativa dos resultados obtidos em provas de carga à tração, com os diversos métodos de previsão de carga última de estacas tracionadas. Os ensaios foram realizados no campo experimental de fundações do Departamento de Geotecnia da USP/São Carlos, sobre estacas apiloadas, escavadas a trado helicoidal e do tipo Strauss, com diâmetros de 20 a 32 cm, e comprimentos de 6 e 9 m. Observou-se que os métodos que consideram a ruptura na interface solo-estaca são os que conduzem a resultados mais satisfatórios de previsão. Ademais, estudou-se a colapsibilidade da ligação solo-estaca, uma vez que as estacas analisadas têm seu fuste embutido em solo de estrutura comprovadamente colapsível. Para tanto, realizaram-se as provas de carga primeiramente com o solo em estado natural e, posteriormente, inundado por 48 h, na carga de trabalho. Constatou-se o colapso da ligação solo-estaca nas cinco estacas, sendo que em três delas - duas escavadas e uma apiloada -, o colapso deu-se na carga de trabalho, com tempos de inundação inferiores a 48 h; nas outras duas estacas, após 48 h de inundação, prossegui-se normalmente com os incrementos de carga, ocorrendo o colapso para 60 e 78% das cargas respectivas de ruptura. / This dissertation deals with an analysis by comparison of results obtained with piles submitted to axial uplift foreces using several prediction methods of ultimate loads. The pile tests were performed in the Experimental Site of the Departament of Geotechnical Engineering of USP/São Carlos, on bored, hammed and Strauss pile types, with diameters varying from 0,20 to 0,32 m and 6 to 9 m long. It was observed that the methods that took into account the pile-soil interface failure yelded better results. Moreover, the pile-soil interface colapsibility was analyzed, once the shaft of the studied piles were embedded in soil whose structure are truly collapsible. For this, pile testings were performed both in the natural soil conditions and soaked during 48 h for working load. Collapse was observed in the pile-soil interface in five piles. For three of them (two of which were bored and one hammed) the failure took place with working loads under 48 h soaking time; in two others, the failure, occured after 48 h soaking time with loads equivalents to 60% and 78% of natural soil\'s ultimate loads, respectively.

Baigiamajame magistro darbe apžvelgti metodai spraustinių polių laikomajai galiai nustatyti. Nagrinėtos dvi metodų grupės – analitiniai ir empiriniai, pagrįsti statinio zondavimo duomenimis. Pagrindinis darbo tikslas yra išanalizuoti ir palyginti nagrinėjamus metodus. Taip pat jie gretinami su eksperimento rezultatais, kas leidžia įvertinti ne tik skirtumus tarp jų, tačiau ir tinkamumą Lietuvos geologinėmis sąlygoms. Eksperimentinę – tiriamąją dalį sudaro geologinio kūno, kuriame įrengti bandomieji poliai, fizikinių – mechaninių savybių apibūdinimas ir polių bandymų įrangos, eigos ir rezultatų aprašymas. Nustatyti pagrindiniai metodų skirtumai, palygintos apskaičiuotos vertės su eksperimento duomenimis. Pateikiamos išvados ir siūlymai tolesniems tyrimams. Darbą sudaro tokios dalys: įvadas, polio apkrovos perdavimas pagrindui, analitinių polio laikomosios galios skaičiavimo metodų apžvalga, empirinių polio laikomosios galios skaičiavimo metodų apžvalga, metodų apibendrinimas, polių bandymas gniuždančia statine apkrova, apskaičiuotų ir eksperimentinių laikomųjų galių gretinimas, išvados ir pasiūlymai, literatūros sąrašas. Darbo apimtis – 64 p. teksto be priedų, 28 iliustr., 10 lent., 39 bibliografiniai šaltiniai. Pridedami darbo priedai. / In master thesis reviewed methods to determine bearing capacity of displacement piles. Two groups of methods analysed – analytical and empirical (based on cone penetration test data). The main aim of the thesis is to overlook and compare with highliting differences of the methods. Also the calculated data is compared with test results. This allows to evaluate the suitability of the methods for Lithuanian geological conditions. Experimental part consists of characteristation of physical – mechanical properties of the geological body where test piles was installed. Also description of test equipment, procedure and results made. Main differences of the methods obtained and test data with calculated values compared. Conclusions and proposals for further investigation represented. Structure: introduction, transmission of pile load to soil, review of analytical methods for determination of pile bearing capacity, review of empirical methods for determination of pile bearing capacity, pile tests on static axial load, comparison of calculated and measured from pile tests results values, conclusions and suggestions, references. Thesis consist of: 64 p. text without appendixes, 28 pictures, 10 tables, 39 bibliographical entries. Appendixes included.

Este trabalho aborda uma análise comparativa dos resultados obtidos em provas de carga à tração, com os diversos métodos de previsão de carga última de estacas tracionadas. Os ensaios foram realizados no campo experimental de fundações do Departamento de Geotecnia da USP/São Carlos, sobre estacas apiloadas, escavadas a trado helicoidal e do tipo Strauss, com diâmetros de 20 a 32 cm, e comprimentos de 6 e 9 m. Observou-se que os métodos que consideram a ruptura na interface solo-estaca são os que conduzem a resultados mais satisfatórios de previsão. Ademais, estudou-se a colapsibilidade da ligação solo-estaca, uma vez que as estacas analisadas têm seu fuste embutido em solo de estrutura comprovadamente colapsível. Para tanto, realizaram-se as provas de carga primeiramente com o solo em estado natural e, posteriormente, inundado por 48 h, na carga de trabalho. Constatou-se o colapso da ligação solo-estaca nas cinco estacas, sendo que em três delas - duas escavadas e uma apiloada -, o colapso deu-se na carga de trabalho, com tempos de inundação inferiores a 48 h; nas outras duas estacas, após 48 h de inundação, prossegui-se normalmente com os incrementos de carga, ocorrendo o colapso para 60 e 78% das cargas respectivas de ruptura. / This dissertation deals with an analysis by comparison of results obtained with piles submitted to axial uplift foreces using several prediction methods of ultimate loads. The pile tests were performed in the Experimental Site of the Departament of Geotechnical Engineering of USP/São Carlos, on bored, hammed and Strauss pile types, with diameters varying from 0,20 to 0,32 m and 6 to 9 m long. It was observed that the methods that took into account the pile-soil interface failure yelded better results. Moreover, the pile-soil interface colapsibility was analyzed, once the shaft of the studied piles were embedded in soil whose structure are truly collapsible. For this, pile testings were performed both in the natural soil conditions and soaked during 48 h for working load. Collapse was observed in the pile-soil interface in five piles. For three of them (two of which were bored and one hammed) the failure took place with working loads under 48 h soaking time; in two others, the failure, occured after 48 h soaking time with loads equivalents to 60% and 78% of natural soil\'s ultimate loads, respectively.

Pile foundations near the crest of a slope are often required to resist lateral loads. This is particularly important for piles at the abutments of bridges. However, limited full-scale test data are available to indicate how the lateral resistance of a pile would be affected when it is located near the crest of a slope. To investigate the effect of a slope on lateral pile resistance, three full scale lateral load tests were conducted on an instrumented steel pipe pile. For the first test, the pile was laterally loaded in horizontal ground. For the second test the pile was at the crest of a 30 degree slope and in the third test the pile was placed three diameters behind the crest of the 30 degree slope. The soil around the pile consisted of clean sand compacted to about 95% of the modified Proctor maximum unit weight for all three tests. Laboratory and in-situ direct shear tests indicated that the friction angle of the sand was approximately 39 degrees. The pile was instrumented with strain gages at approximately 1.5 ft intervals along its length so that the bending moment versus depth profile could be determined. Pile head load, deflection, and rotation were also measured. Based on the results, the presence of the slope decreased the ultimate lateral resistance of the pile-soil system by approximately 25% and 10% for tests two and three, respectively. The presence of the slope also resulted in an increase in the maximum bending moment of approximately 40% and 30% for tests two and three, respectively. Analyses using LPILE matched the lateral resistance for the pile in horizontal ground, but significantly overestimated the decrease in resistance due to the sloping ground. A mathematical model was developed to predict the ultimate strength of a pile located some distance from the crest of a cohesionless sloping profile. Parametric test results using the model were within 2.6 % of the measured results of tests two and three.