Jonas Amšiejus

Study of bearing capacity of vibratory pile applying acceleration record

AbstractThe article focuses on the method for evaluation of ultimate bearing capacity for a vibratory pile having acceleration data recorded during the tests. The simulation vibratory pile installation test was performed in the testing stand. Accelerations were recorded on the top of the simulation vibratory pile during the test. The static test was performed for the installed pile. After the review of rheological models of the base, the Smith rheological model was chosen for determination of bearing capacity of the vibratory pile as this model, the rigidity of the final element of the spring is modelled as the finite rigidity of the base. Between the base of the modelled pile and the soil, a finite interface element is used. The interface element transfers only compression but it does not transfer tension to the base rheological model. The general stiffness of springs finite element in the chosen rheological model is determined from experimental data of the static pile test. During the modelling, the da...

Experimental and numerical investigation of sand compression peculiarities

Abstract Investigation of the compression properties of Klaipėda sand by oedometric testing and numerical modeling is presented. Klaipėda sand is characteristic of the Baltic seashore region sand. Experimental investigation was performed with fraction corresponding to diameter variation bounds of 0.6 and 0.425 mm. Compression test was realized with initial maximal void ratio (e 0 = 0.800) of sand. Employed vertical stress ramp value is 800.0 kPa/min, maximum loading σmax = 400.0 kPa. Applying loading within the range of 50.0 to 120.0, two vertical stress jumps have been identified. A rubber sample compression test has been performed aiming to deny an assumption, that vertical stress jumps are influenced by device construction. Experiment viewed that not any vertical stress jumps have been recognized. Numerical simulation yielded exactly the same two vertical stress jumps found by compression with oedometer. It proves that the nature of rearrangement of sand grains has been properly reflected by modeling c...

Inžinerinis metodas taško nuosėdžiui skaičiuoti nuo gretutinės apskritiminės tolygiai išskirstytos apkrovos

Santrauka Tiesiskai deformuojamo puserdvio, apkrauto apskritimine tolygiai isskirstyta apkrova, vertikalieji poslinkiai apskaiciuojami integruojant Businesko sprendinio vertikaliojo poslinkio israiską apkrautame plote. Sis integralas apskaiciuojamas sumavimo metodu. Darbe pateiktas tiesiskai deformuojamo pagrindo, apkrauto apskritimine tolygiai isskirstyta apkrova, nuosėdžių skaiciavimo metodas yra gana tikslus. Siuo metodu galima įvertinti puserdvio pavirsiaus nuosėdį ne tik nuo apskritiminės tolygiai isskirstytos apkrovos, bet ir nuo kitų, greta esancių apskritiminių tolygiai isskirstytų apkrovų. Inžineriniam metodui realizuoti taikytas sumavimo principas, pakeiciantis tiesioginį integravimą reikiamu tikslumu. Tuo tikslu sukurtas sumavimo algoritmas, jį realizuojanti kompiuterinė programa. Inžinerinis poslinkio skaiciavimo metodas realizuotas laipsnine lygtimi ir jam taikyti patogia naudoti nomogramų forma. Taikant sukurtą inžinerinį metodą atliktas nuosėdžių apskaiciavimo skaitinis modeliavimas. Atliku...