The Effect of Log Piling on Liquefaction

Abstract

This paper introduces a liquefaction mitigation method that uses log piles as environmentally friendly and practical solution for strengthening civil engineering structures. The liquefaction mitigation measure explored in this paper can be used to increase the earthquake resistance of loose sands by improving the density of soil. During the Tohoku Pacific earthquake in 2011, liquefaction was pervasive in large portions of the region, especially in Tokyo Bay and the city of Urayasu. Extensive liquefaction caused extensive damage to residential properties, electricity, water, sewage networks, and bridges. The mitigation of global warming is an important issue that requires immediate attention. Because the use of wood can be effective for preventing global warming, the authors have considered it to mitigate liquefaction damage. A series of large-scale shaking table tests was performed to investigate the effect of liquefaction mitigation by log piling into sandy ground. The results indicate that the method of log piling is an effective liquefaction mitigation compared with methods for increasing density, such as the densification method. Portable dynamic cone penetration (PDCP), Swedish weight sounding (SWS), automatic ram sounding (ARS), piezo drive cone (PDC), and flat dilatometer (FDM) tests, as well as field tests, were performed in the city of Urayasu. These tests were performed to confirm the effectiveness of log piling on liquefaction mitigation.

Microbiological community structure on logs used for groynes in a riverbank system

“…These facts suggest that members of this fungal genus can degrade wood in the presence of oxygen, as in the aerial section, but might not be capable of wood decay under an oxygen-deficient environment. Wood, used in underwater construction work such as water groynes, or in underground construction such as a Log Piling Method for Liquefaction Mitigation and Carbon Stock (LP-LiC method) [33][34][35], is considered to have a long service life because the degradation activity of wood-rotting fungi that use oxygen is almost completely stopped and the deterioration in strength progresses very slowly [36]. In this study, in a stable underwater environment with small fluctuations in water level, almost no wood deterioration by fungi occurred.…”

State-of-the-Art Application of the Log-Piling Method in the Role of Shallow Ground Improvement for Liquefaction Mitigation

“…Presented as an approach that concurrently addresses concerns regarding carbon stock and liquefaction mitigation, a method involving the static installation of timber piles for soil densification and reinforcement has been introduced as shown in Figure 2. This conceptual framework, developed in recent years, seeks to alleviate excess pore water pressure and mitigate structural settlement [2]. Prior investigations into the utilization of log piles for liquefaction mitigation have already demonstrated their efficacy.…”