Centrifuge liquefaction tests in a laminar box

Abstract

The difficulties associated with instrumenting earthquake sites in order to record pore pressure changes in a future event led to the use of scaled model tests performed in a centrifuge. Both dry and saturated sands were employed, contained in a box constructed of aluminium laminae designed to move freely on each other. This would result in shearing distortions developing in the soil unimpeded by the container. Accelerometers, displacement transducers and pore pressure sensors were attached to the box and embedded in the soil at various elevations so as to record the response of the soil to an earthquake-like excitation supplied to the base of the container. A special apparatus was constructed to imitate earthquake motion. In some tests on saturated sand, the soil profile was liquefied. Test results of accelerations, lateral and vertical displacements and pore pressures against time for typical earthquake inputs are given. The data, obtained under controlled conditions, can be compared with the various calculation methods for dynamically generated pore pressures.

Effect of shaking strength on the seismic response of liquefiable level ground

“…The permanent settlement of the ground surface was 0.364 m, corresponding to a vertical strain of about 2.3% over the 16 m layer thickness. The vertical strain in Test B and those in the tests reported by Hushmand et al (1988), Arulanandan and Sybico (1992), and Taboada and Dobry (1993) is of the same order in spite of the difference in the shaking duration and strength. It is also noted that, in accordance with the observations by Arulanandan and Sybico (1992), and Taboada and Dobry (1993), most of the settlement was developed during the shaking event.…”

“…To simulate the free-field boundary condition, stacked-ring model containers and laminar boxes have been widely used to accommodate the soil column subjected to horizontal one-dimensional earthquake excitation (e.g., Hushmand et al (1988), Taboada and Dobry (1993)). A laminar box that allows free motion in any horizontal direction was used in this study to minimize the boundary effect of the container on the model behavior under two-dimensional shaking.…”

Centrifuge model test on earthquake-induced differential settlement of foundation on cohesive ground

“…The size of shaking table is 0.95 m× 0.65 m. Under centrifuge acceleration 50 g, the centri- fuge accommodates a maximum payload of 300 kg at shaking acceleration 10 g for arbitrary wave and 5 g for sinusoidal wave respectively, with frequency range of 50-350 Hz [25] . The laminar container used in this study consists of 13 rectangular frames made of square steel tubing, with linear bearings 2 mm high installed between these frames [26] . The inside dimensions of the container are 74 cm long, 37 cm wide and 32 cm deep.…”

Study of Physical Modelling for Piles

“…During these years some researchers designed various wall systems. Hushmand (1988 and developed it to a multi layered box which horizontal movements imposed on various levels of the devices [14]- [19]. According to Ahmadi, Eslami and Arabani (2016), now, at being time the laminar boxes usually insist of a series of laminar segments, each 50 mm or less in height, which can freely move over each other in one direction.…”