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Introduction. Soil reinforcement is widely used in the construction of buildings and structures in complex geological conditions, especially with the help of vertical elements. Calculations of reinforced foundations in practice are carried out by various methods, including numerical methods. Many studies were carried out on soil behaviour during pile reinforcement and its effect on settlement, but the interaction between soils and reinforcing elements is not fully understood. The choice of element location and assessment of the influence of soil liquefaction on the reinforcement efficiency under seismic effects remain topical tasks.Materials and methods. The effects of different reinforcing pile arrangements on the behaviour of the soil mass and foundation settlement under seismic loads are studied. Three pile arrangements, including conventional and alternative arrangements are considered using the PLAXIS 2D programme. Different soil models are also used in the calculation — UBC3D-PLM and HS Small for modelling the bottom and top layer of the soil depending on its characteristics.Results. The results show that all three selected design schemes obtain a significant increase in settlement during earthquake passage. The different pile arrangements significantly affect the deformation and settlement of the foundation slab, as well as the location of soil liquefaction points under seismic loads.Conclusions. By changing the parameters of pile reinforcement, it is possible to control the size and location of liquefaction zones and, if necessary, to protect some zones from the realization of this process. The presented results can contribute to the design and development of effective methods of construction in earthquake-prone areas.

Interpretations of seismic, gravity and magnetic anomalies and structural data on the coastal zone of southern part of Central Viet Nam (SCVN) and the adjacent Tertiary basins suggest several phases in the tectonic evolution of the study region since the Late Cretaceous to Quaternary. In this paper, we try to clarify the tectonic evolution of SCVN and the adjacent continental margin. The Cretaceous – Paleocene tectonic phase commenced after cessation of the West Pacific plutonic magmatic activity that produced numerous diabases and aplite dykes of mainly sub-meridian orientation. It was characterized by N–S compression and E–W extension. The geomorphology and geology ofSE Asiawere considerably changed during the Neotectonic phases caused by collision between the Indian plate and the Eurasian continent. Two tectonic phases – Early and Late Neotectonic – are separated by a regional unconformity represented by a boundary surface between below strongly deformed strata (synrift) and above less deformed formations (post-rift). The Early Neotectonic phase was related to the left-lateral movement of the Red River Fault Zone (RRFZ) and includes two tectonic sub-phases: Eocene – Oligocene (NW–SE compression), and Oligocene – Miocene (E–W compression). Activity in the Oligocene-Miocene sub-phase gave birth to rift basins in the continental margin of the SCVN. The Late Neotectonic phase began since the RRFZ stopped left-lateral movement and the East Viet Nam (orSouth China) Sea stopped spreading. The Late Neotectonic phase is also divided into two tectonic sub-phases: Late Early Miocene (sub-meridian compression), and Late Miocene – Pliocene (NE–SW compression). The Late Miocene – Pliocene sub-phase is characterized by vertical movements that caused episodic uplifting of the onland terrains, and subsidence of the offshore Phu Khanh basin. Besides, Miocene – Pliocene-Quarternary basaltic eruptions were widespread all over the southern Indosinian terrain and the continental margin.