Geotechnical engineering applications have been conducted in China for very long time. After studying on the related ancient documents, it was realized that good achievements have been reached by ancient Chinese in many geotechnical aspects : boring inspection, soil compaction, column structure, raft foundation, timber pile application, temporary water-stop work, seepage control, earth reinforcement, tunneling, deep excavation, construction equipment,earthquake record and earthquake monitoring device etc.The readers are also reminded to work hard to succeed to their ancestor’s remarkable achievements.
The 2016 Meinong Earthquake is the most deadly earthquake occurring in Taiwan after the 1999 Chi-Chi Earthquake. This study focuses on the co-seismic displacements of the Meinong Earthquake, and the interseismic crustal deformation pattern near the epicenter area. The co-seismic displacement and interseismic deformation rate measured by the continual GPS stations, leveling, D-InSAR, and PS-InSAR. The data suggest both the co-seismic displacement and interseismic crustal deformation rate dominated by a duplex structure underneath the Lungchuan Fault, which is about 10 km west of the epicenter. Most of the deformations concentrated in the area where the Gutingken Formation exposed. The interseismic deformation rate resulting from the duplex structure can reach several centimeters per year. The high deformation rate makes some damage on a bridge and two tunnels of the Freeway No. 3 above the duplex structure. The high deformation rate might be the result of the overpressured zones in the Gutingken Formation. The Gutingken Formation contains several overpressured zones, and fractures in the Gutingken Formation can be lubricated by the high pressure fluid. As a result, the faults in the Gutingken could be triggered by the Meinong Earthquake, and generated large magnitude of co-seismic displacements.
On 6 February 2016, a local magnitude (ML) 6.6 earthquake struck southern Taiwan, contributing to devastation in the Tainan area. In this paper, geotechnical damage features caused by the earthquake are documented by field investigations conducted by a survey team from the National Center for Earthquake Engineering (NCREE). The reconnaissance includes liquefaction at Hui-An St and Sanmin St., the levee failure of Zen-Wen River at the Jianshan and Rixin sections, a landslide at the Nan-Bao Golf Course, and the performance of the Hutoupi dam. Based on the field survey, lessons learned from the damage and the future study are summarized in the conclusion.
On February 6, 2016, an earthquake happened occurred with ML6.6 in south Taiwan. The epicenter of the earthquake was located in Kaohsiung, but the earthquake caused severe damage 20 km away in Tainan city, including soil liquefaction, the collapse of a high rise building, damage to residential houses, and the displacement of bridges. Reports of the Central Weather Bureau, Taiwan, show that Tainan City reached seismic intensity level V. Moreover, the soil liquefactions occurred in the northwest and northeast parts of the Tainan tableland, in the An-nan District, North District, and West Central District, and Sinshih District. Structures were damaged in the south and the southeast parts of the Tainan tableland, in the East District, Gueiren District, Guanmiao District, and Yujing District. Geotechnical environment may be a key factor to investigating the distribution of the disasters. This paper discusses the changes of sedimentary environment from the movement of the coast in Tainan. Then, the impact of the geotechnical properties in different sedimentary environments are examined to investigate the damage distributions by the borehole data.
The discussed zone, with major seismic damages, is between the Erren River in the south and Tsengwen River to the north. The paper serve as a reference to increase the seismic resistance of Tainan city.
Numerous buildings were damaged seriously during Meinong Earthquake. A great deal of building damage was induced by soil liquefaction. Citizens have paid significant attention to liquefaction issues after this event. In this paper, a preliminary investigation report of the liquefied sites presented and a case study of the reliquefaction area is conducted. Mapping the locations of sand boils domes during two events shows a lot of points overlap. The analysis result of a CPT-based liquefaction potential index of the reliquefied site indicates this site is categorized as a medium liquefaction hazard area.
On February 6th, 2016, an earthquake of magnitude 6.5 occurred in Meinong, Kaohsiung, at 3:57 AM. The intensity measured in Tainan was 5, with several other earthquakes of intensities from 3 to 4 occurring in Guiren, Guanmiao, and Shinshi. The earthquake caused severe damage to the city of Tainan. 116 people were found dead, and several buildings were tilted or damaged. Power and water outages caused by the earthquake affected nearly 120,000 homes, and a main water pipe was destroyed in Yongkang. The February 6th earthquake also induced soil liquefaction in a great number of locations in Tainan, which caused damage to building structures, roads, bridges, and earth retaining and levee structures. Among them, soil liquefaction at the levee of the Tsenwen River, in Danei, caused flow liquefaction and lateral spread damage to the levee structure in Rishin and Jianshan. This paper investigates damage to hydraulic facilities, including the cause of damage and methods of reconstruction, and provides a reference for future evaluation and improvement.
Post-earthquake reconnaissance is usually resource demanding a task. However, it is crucial for human society to recover from the impacts of natural disasters. Existing technical applications of using terrestrial laser scanning (TLS) for post-earthquake reconnaissance are not frequently seen yet but its potential has been revealed recently. Specifically a quantified damage estimation of building structures can be assisted by TLS through dense point cloud data analysis. Furthermore, the geographical changes such as landfall of targeted areas can be analyzed and traced after significant ground movement events. This study aims at exploring the capabilities of terrestrial laser scanning in assisting post-earthquake reconnaissance. The first exploration is to reconstruct the scenes of building subsidence due to soil liquefaction during earthquake excitations. The overall building tilt and subsidence can be evaluated by accessing the dense point cloud data. The second exploration is to accurately reflect the geographical states of vulnerable areas, which can further serve as the quantified geo-log for tracing the long-term variations. In conclusion, this study showcased the feasibility and applications of TLS for post-earthquake reconnaissance.
The Meinong earthquake on 2016/02/06 triggered severe liquefaction failures of residential sites in Tainan City, where is about 45km from the epicenter. The foundation and ground failures raise public attentions on liquefaction potential of residential areas. To perform quick damage assessments and conduct effective recovery and mediation strategies, the soil stratum information regarding the liquefaction potential is crucial. The reconnaissance reports reveal that the liquefied residential areas were in old ponds or water area before the construction and liquefaction occurred in the loose, backfill, granular layers. For these highly isolated and nonhomogeneous sites, conventional drilling and penetration techniques are limited in terms of time, cost, and data density. To overcome these limitations, a surface wave technique was adopted to determine the shear wave velocity profiles of liquefied sites and adjacent non-liquefied sites. Liquefaction evaluations using shear wave velocity were conducted to determine the liquefied layer. The liquefaction analyses agree with the historical maps, regional geotechnical properties, and field observations. The results support that surface wave techniques can be an effective tool for quick damage assessments as well as an alternative to reduce the boring density for mapping of liquefaction potential.
The most widespread and intensive soil liquefaction induced damages on buildings occurred in the Si- Ding area, Annan District, Tainan during the 2016 Meinong Earthquake. Around 300 buildings, more than 80% of which were row houses that were around 35 years old, as well as individual house and newer row houses which had been remodeled, and had various foundation types. After the earthquake, a soil liquefaction hazard map was drawn according the observed ejected soils by my team since Feb. 9 and the people living in the neighborhood. Moreover, the damaged building with various foundation types were marked on the same map to give us a better idea of the damage mechanism; and countermeasures against soil liquefaction for the buildings in this area are suggested.
Damages caused by the MeiNong Earthquake, 2016, required further efforts on the disaster mitigations in Tainan. Kyoto is an important historical city in Japan. Numerous seismic-induced disasters are available in the history. Experiences to mitigate the earthquake-induced disasters in Kyoto are valuable references to Tainan. In Kyoto, the disaster mitigation is based on evaluating the ground response of an earthquake by clarifying the depth and the distribution of rock mass and each soil layer lying above. The movement of Hanaore Fault, which is an inland fault, and the Nankai Trough are considered as the major threats to Kyoto. Then, damages caused by soil liquefactions, failure of structures, and fires are evaluated. The damage information can be used to the city constructions, team-work promotion, and the systematic reaction and recovery of a city with high disaster resistances. In addition, most cultural properties are made of wood. Their reinforcement and the stop of fire spread must involve the neighbor zones. More, Kyoto is a sight-seeing city. The foreign tourists must be secured when the disaster happens.