Influences of Long-Term Tectonic and Geo-Climatic Effects on Geotechnical Problems of Soft Ground - Ulaanbaatar, Mongolia

2016 ◽  
Vol 18 (1) ◽  
pp. 51-58
Author(s):  
S. Manandhar ◽  
T. Hino ◽  
K. Kitagawa
Keyword(s):  
Soft Ground ◽  
Climatic Effects ◽  
Geotechnical Problems

scholarly journals Mechanical Properties of Cement-Treated Soil Mixed with Cellulose Nanofibre

2021 ◽  
Vol 11 (14) ◽  
pp. 6425
Author(s):  
Hidenori Takahashi ◽  
Shinya Omori ◽  
Hideyuki Asada ◽  
Hirofumi Fukawa ◽  
Yusuke Gotoh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Geotechnical Engineering ◽  
Strength Development ◽  
Soft Ground ◽  
Wood Cellulose ◽  
Treated Soil ◽  
Made In ◽  
Cement Treatment

Cellulose nanofibre (CNF), a material composed of ultrafine fibres of wood cellulose fibrillated to nano-order level, is expected to be widely used because of its excellent properties. However, in the field of geotechnical engineering, almost no progress has been made in the development of techniques for using CNFs. The authors have focused on the use of CNF as an additive in cement treatment for soft ground, where cement is added to solidify the ground, because CNF can reduce the problems associated with cement-treated soil. This paper presents the results of a study on the method of mixing CNF, the strength and its variation obtained by adding CNF, and the change in permeability. CNF had the effect of mixing the cement evenly and reducing the variation in the strength of the treated soil. The CNF mixture increased the strength at the initial age but reduced the strength development in the long term. The addition of CNF also increased the flexural strength, although it hardly changed the permeability.

scholarly journals Assessment of the climate changes evolution for the long-term safety of the radioactive waste repository in the Czech Republic

2019 ◽  
Vol 133 ◽  
pp. 02005
Author(s):  
Markéta Camfrlová
Keyword(s):  
Czech Republic ◽  
Radioactive Waste ◽  
Spent Nuclear Fuel ◽  
Global Climate ◽  
Deep Geological Repository ◽  
Climatic Effects ◽  
The Czech Republic ◽  
Area Of Interest ◽  
Geological Repository

Nuclear energy accounts for a significant part of the total energy production in the Czech Republic, which is currently facing a problem dealing with the high-level radioactive waste (HLW) and the spent nuclear fuel (SNF). Deep repository is the safest option for storage of HLW. Rock environment of the area must guarantee the stability of the deep geological repository for at least 100,000 years. The aim of the research is a long-term evaluation of the climatic changes of the hypothetical area of interest, which corresponds to the candidate sites for deep geological repository in the Czech Republic. The occurrences of endogenous and exogenous phenomena, which could affect site stability, were evaluated. Concerning exogenous processes, research focuses mainly on the assessment of climatic effects. The climate scenarios for the Central Europe were examined – global climate change, glaciation, and the depth of permafrost as well as CO2 increase.

Laboratory Investigations on the Effects of Bacteria on Fine-Grained Soils

2017 ◽  
Vol 21 ◽  
pp. 352-357 ◽  
Author(s):  
S. Sowmya ◽  
P.S. Meenu ◽  
R. Asha Latha ◽  
Devendra Narain Singh
Keyword(s):  
Preliminary Investigation ◽  
Biological Processes ◽  
Fine Grained ◽  
Recent Developments ◽  
Prospective Application ◽  
Laboratory Investigations ◽  
The Impact ◽  
Geotechnical Problems ◽  
Long Term Studies

Over the years, the field of geotechnical engineering focused on physical, chemical and mechanical aspects of the geomaterials. However, recent developments in environmental geotechnics have highlighted the impact of biological processes on geo-materials and their performance. Also, the present day geotechnical problems favour biological interventions to develop eco-friendly and sustainable technology. In view of this, the present study is a preliminary investigation on the impact of microbial loading on fine-grained soils. In addition, a protocol has been developed to establish ‘bio-geo interface’ between bacteria and the geo-material. However, long term studies are demanded in this direction for in-depth understanding of the mechanism for development of prospective application.

Case Study of Long-Term Ground Settlements Induced by Slurry Shield Tunnelling

2011 ◽  
Vol 243-249 ◽  
pp. 3078-3081 ◽  
Author(s):  
Cun Gang Lin ◽  
Zhong Miao Zhang ◽  
Shi Ming Wu
Keyword(s):  
Careful Analysis ◽  
Soft Ground ◽  
Road Tunnel ◽  
Shield Tunneling ◽  
Shield Tunnelling ◽  
Slurry Shield ◽  
Settlement Time ◽  
Ground Settlements

The Qing-chun Road Cross-river Tunnel is the first road tunnel under the Qiantang River in Hangzhou, and it is also the first experiences of slurry shield tunnelling in Hangzhou soft ground. In order to ensure the safety of construction and reduction of environmental impacts while shield tunnelling, a comprehensive monitoring system was carried out during construction, which included ground settlements, displacements and deformations of installed linings and so on. In this paper, the long-term ground settlements induced by slurry shield tunnelling were described in detail, and careful analysis of monitoring ground settlements was made. This case study shows that: 1. The surface transverse consolidation settlements do not follow the Gaussian curve; usually the largest settlements exist above the centerline of the tunnel or nearby, from where settlements descend outwards. Due to consolidation, the surface settlement troughs widen with time.2. Shield tunneling in soft ground, the turning point in settlement-time curves or settlement rate-time curves can be chosen as the time divides the immediate and long-term consolidation settlements.

scholarly journals Experimental Evaluation of Construction Performance and Long-term Settlements in Soft Ground Breakwater

2003 ◽  
Vol 25 (spc3) ◽  
pp. 385-392
Author(s):  
O-Soon Kwon ◽  
In-Sung Jang ◽  
Woo-Sun Park ◽  
Ki-Dai Yum
Keyword(s):  
Experimental Evaluation ◽  
Soft Ground

scholarly journals An Index for Depicting the Long-Term Variability of Mesoscale Eddy Activity over the Kuroshio Extension Region

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 792
Author(s):  
Peilong Yu ◽  
Chao Zhang ◽  
Lifeng Zhang ◽  
Xiong Chen ◽  
Quanjia Zhong ◽  
...  
Keyword(s):  
Activity Index ◽  
Kuroshio Extension ◽  
Mesoscale Eddy ◽  
Low Frequency ◽  
Climatic Effects ◽  
Near Surface ◽  
Eddy Activity ◽  
Frequency Changes ◽  
The Kuroshio

Using high-resolution satellite-derived sea surface temperature (SST) data from September 1981 to December 2015, the present study develops a new index to detect the long-term variation in mesoscale eddy activity over the Kuroshio Extension (KE) region. This eddy activity index (EAI) highlights the strength of eddy-induced poleward heat transport and has obvious advantages over the other existing KE indices in depicting the low-frequency changes in KE eddy activity. An analysis of the EAI shows that over the long term, the KE eddy activity variability presents a significant spectral peak of about 8 years and is not directly modulated by wind-driven oceanic Rossby waves generated in the central North Pacific. When the EAI is positive, the strengthened KE eddy activity significantly enhances the heat release from ocean to atmosphere over the Kuroshio–Oyashio confluence region (KOCR). This induces an anomalous dipole pattern of near-surface baroclinicity over this region that can persist for up to 6 months, favoring a weakened and northward-moving East Asian jet, and vice versa. It is believed that the new EAI will facilitate future studies focusing on the climatic effects of the KE eddy activity variation.

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