ALBERT

Beschreibung: 〈p〉Publication date: Available online 25 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soils and Foundations〈/p〉 〈p〉Author(s): Jia-jin Zhou, Jian-lin Yu, Xiao-nan Gong, Ri-hong Zhang, Tian-long Yan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a field study on the uplift bearing capacity of a pre-stressed high-strength concrete (PHC) pile embedded in clayey soil, and on the soil around the PHC pile that was treated with cement paste. The PHC pile was inserted into a pile hole filled with cemented soil by its own weight (by gravity), and the soil compaction effect of a conventionally driven pile induced by the installation process was avoided. The test results showed that: the pile head displacement needed to fully mobilize the uplift bearing capacity of the test piles was about 0.1 D (pile diameter); the ultimate skin friction of the PHC pile–cemented soil interface was much larger than that of the cemented soil–soil interface; the PHC pile and the cemented soil around the pile behaved as an integral pile in the load transfer process; and the measured ultimate bearing capacity of the test piles was 0.91–0.94 times the American Petroleum Institute (API)’s proposed values for piles under compression and 0.79–0.80 times the values calculated with the effective stress method for piles under compression.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 17 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soils and Foundations〈/p〉 〈p〉Author(s): Chenghua Shi, Qianjin Zhao, Mingfeng Lei, Menglong Peng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the rapid development and construction of China’s transportation system, more and more projects are being conducted near existing buried pipelines, which will inevitably influence the safety of the pipelines. Among the safety issues related to buried pipelines, blasting during the construction of an adjacent tunnel is one of the most adverse factors for existing pipelines. To ensure the safety and normal operation of the pipelines, a method for determining the peak vibration velocity control standard for buried pipelines under blast loading is established in this study. The acceleration time-history function that acts on the rock mass under the blasting seismic wave is derived as external excitation acting on the pipeline. By using the acceleration time-history function as input and combining it with a dynamic and static analysis of the pipeline, the critical vibration velocity of pipelines under the action of blast loading can be determined by the von Mises yield criterion of the buried pipeline material. Using the Dashanpi No. 1 tunnel project in Shenzhen, China as a background, the critical velocity control standard for buried pipelines under tunnel blast loading can be set at 190 mm/s without considering either the initial defects or the corrosion conditions during the operation.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 17 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soils and Foundations〈/p〉 〈p〉Author(s): Shinichiro Mori, Kohei Ono〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In early July 2018, record heavy rainfalls caused enormous damage from western Japan to the Tokai region. In particular, Hiroshima, Okayama, and Ehime Prefectures suffered extensive human casualties and tremendous damage to housing units and the infrastructure due to landslides and river flooding. The authors conducted a series of reconnaissance operations and analyzed various kinds of data, including rainfall records, aerial photographs, official statistics of the disasters, and topographical and geological maps of Ehime Prefecture. In this report, the authors focus on the rainfall characteristics, geological background, and landslide statistics and distributions associated with the July 2018 events, and present examples of typical damage by geological belt. Based on this, they discuss several characteristics of the landslides, including the rainfall thresholds by geological belt, the characteristics of the runout distance of the debris flows, and the rainfall thresholds for landslide initiation in terms of the Soil Water Index (SWI). Based on an official database of a total of 413 landslides occurring in Ehime Prefecture and the authors’ newly developed database of 883 landslides in the southern part of the prefecture, several findings were obtained, for example, that slopes in the Shimanto Belt had a lower rainfall threshold for landslide initiation than slopes in the other two geological belts, namely, Sambagawa and Chichibu Belts.〈/p〉〈/div〉 〈/div〉