Maxim Millen

Bio: Maxim Millen is an academic researcher from University of Canterbury. The author has contributed to research in topics: Liquefaction & Foundation (engineering). The author has an hindex of 4, co-authored 19 publications receiving 56 citations. Previous affiliations of Maxim Millen include University of Porto.

Physical and numerical modelling of dry granular flows under Coriolis conditions

Abstract: In this paper, quantitative observations of dry granular flows subject to varying magnitude and direction of Coriolis acceleration are presented in order to assess the robustness of the Savage–Hutt...

Ground Motion Characteristics Estimated from Spectral Ratio between Horizontal and Verticcl Components of Mietremors.

Abstract: The spectral ratio between horizontal and vertical components (H/V ratio) of microtremors measured at the ground surface has been used to estimate fundamental periods and amplification factors of a site, although this technique lacks theoretical background. The aim of this article is to formulate the H/V technique in terms of the characteristics of Rayleigh and Love waves, and to contribute to improve the technique. The improvement includes use of not only peaks but also troughs in the H/V ratio for reliable estimation of the period and use of a newly proposed smoothing function for better estimation of the amplification factor. The formulation leads to a simple formula for the amplification factor expressed with the H/V ratio. With microtremor data measured at 546 junior high schools in 23 wards of Tokyo, the improved technique is applied to mapping site periods and amplification factors in the area.

On Dense Granular Flows Down Flat Frictional Inclines

Abstract: We consider dense, relatively shallow flows of 3 mm glass spheres moving down a chute with a flat, frictional base of 3.6 m length. Sustained flows are observed at inclinations corresponding to an effective friction between the static and dynamic friction of individual grains. A capacitance instrument records the formation of waves with a dominant component traveling upstream. Simultaneous measurements of granular temperature at the base using a load cell reveal that the waves are accompanied by substantial reduction in granular agitation. A theory incorporating contributions from impulsive and enduring interactions with the base produces quantitative predictions for the range of sustained flows observed in the experiments. Closure of the theory is achieved using a balance between the production and dissipation of angular momentum in a narrow basal shear layer. A linear stability analysis of the corresponding hydraulic equations further suggests the origin of the waves.

Impact mechanisms of granular and viscous flows on rigid and flexible barriers

Abstract: Structural countermeasures such as rigid and flexible barriers are commonly installed in mountainous regions to intercept mass-wasting processes. Without sufficient and reliable comparable physical data, the study of impact mechanisms remains difficult and not well understood. In this study, a newly developed flexible model barrier together with a rigid barrier are used to simulate either dry granular or viscous liquid impacts on these model barriers in a geotechnical centrifuge. The novel flexible barrier is made of four instrumented cables controlled by spring mechanisms to replicate a bilinear prototype loading response. Tests revealed that regardless of barrier type, both dry granular and viscous flows could have similar frontal dynamic impact coefficients around unity. Compared with the kinetic energy of flow mass (∼10 MJ), only 249 kJ of flexible barrier energy capacity was mobilized. This implies that debris-resisting barriers may only be required to intercept the dynamic flow front as the subseque...

Influence of debris flow solid fraction on rigid barrier impact

Abstract: The dynamics of debris flows are fundamentally governed by the interaction between the solid and fluid phases. However, current approaches used to estimate impact load treat debris flow as an equiv...

Investigating six-degree-of-freedom loading of shallow foundations on sand - Discussion

Abstract: Laboratory studies of the response of shallow foundations have previously considered only planar loading. This paper describes experimental work carried out using a loading device that applies general loading onto model shallow foundations. The loading, involving all six degrees of freedom [vertical (V), horizontal (H2, H3), torsion (Q) and overturning moment (M2, M3)], has been applied to a 150 mm diameter circular flat rough foundation on a loose dry silica sand. Aspects of the loading rig design are briefly described, but the main focus is the presentation of the experimental results. These provide evidence for the generalisation of existing work-hardening plasticity models from planar loading to general loading conditions. This evidence is used to extend an existing numerical model to the six-degree-of-freedom case, and the simulation results are compared with the experimental results.