A series of 1-g shaking table model tests were carried out to study the behavior of pile groups embedded in sloping ground subjected to lateral ‰ow of liqueˆed soil. Two diŠerent conˆgurations of pile groups: large (6×6 and 11×11) and small (3×3), were considered. The models were subjected to the liquefaction-induced large ground deformation to investigate the eŠect of several parameters on the response of pile groups and mechanism of lateral ‰ow. These parameters comprise amplitude, frequency, and direction of input motion; density and slope of ground; and the thickness of non-liqueˆable layer at the surface. The outcome of this parametric study reveals the importance of above mentioned factors which should be taken into account for analysis and design purposes. In addition, the results from the experiments clearly illustrate that in sloping ground conˆguration, both front (in upstream) and rear (in downstream) row piles receive greater lateral forces than middle row piles. Thisˆnding is attributed to the distribution of soil motion (displacement and velocity) of the liqueˆed soil in the model. As a result, installation of additional pile rows in front and behind an existing pile foundation can be considered as an eŠective retroˆtting technique. Finally, soil-pile interaction was evaluated by running experiments with diŠerent pile spacings, and reliability of the JRA 2002 design manual in estimation of liquefaction-induced lateral force on piles is evaluated.

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UVODRealna procena dinami ki indukovanih prese nih sila u tunelskoj konstrukciji predstavlja veoma važan aspekt aseizmi kog projektovanja tunelskih objekata. U analizi odgovora tunelskih konstrukcija na seizmi ke uticaje, koriste se dva postupka: metoda slobodnih deformacija tla i metoda interakcije konstrukcije i tla [6,23].Najjednostavniji pristup u analizi seizmi kog odgovora tunelskih konstrukcija jeste metoda slobodnih deformacija tla. Termin slobodna deformacija tla opisuje deformaciju usled prostiranja seizmi kih talasa u tlu bez tunelske konstrukcije ili iskopa. Ideja ovog pojednostavljenog postupka jeste sra unavanje seizmi ki indukovanih deformacija tla u odsustvu tunelskog objekta, nanošenje tako sra unatih deformacija tla na tunelsku konstrukciju u stati kim uslovima, i projektovanje tunelske konstrukcije za tako definisano optere enje. Samim tim, ovim postupkom krutost tunelske konstrukcije nije uzeta u obzir, ime je interakcija konstrukcije i okolnog tla zanemarena. Ipak, ovom metodom je mogu a veoma jednostavna i brza procena reakcije konstrukcije na seizmi ka dejstva. Veli ine deformacija tunelske konstrukcije Asistent Elefterija Zlatanovi , dipl.inž.gra . Univerzitet u Nišu, Gra evinsko-arhitektonski fakultet,

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In geotechnical engineering, numerical simulation of problems is of great importance. This work proposes a new formulation of coupled finite-infinite elements which can be used in numerical simulation of geotechnical problems in both static and dynamic conditions. Formulation and various implementation aspects of the proposed coupled finite-infinite elements are carefully discussed. To the authors' knowledge, this approach that considers coupled finite-infinite elements is more efficient in the sense that appropriate and accurate results are obtained by using less elements. The accuracy and efficiency of the proposed approach is considered by comparing the obtained results with analytical and numerical results. In a static case, the problem of circular domain of infinite length is considered. In a dynamic case, one dimensional wave propagation problems arising from the Heaviside step function and impulse functions are considered. In order to get a more complete picture, two dimensional wave propagation in a circular quarter space is considered and the results are presented. Finally, a soil-structure interaction system subjected to seismic excitation is analyzed. In the analysis of soil-structure interaction phenomenon, frames with different number of storeys and soil media with various stiffness characteristics have been taken into consideration. In the analysis, the finite element software ANSYS has been used. For the newly developed infinite element, the programming has been done by the help of the User Programmable Features of the ANSYS software, which enable creating new elements in the ANSYS software.