scholarly journals Investigating High-Strength Expanded Polystyrene (HS-EPS) as yielding support elements for tunnelling in squeezing ground conditions

2021 ◽  
Vol 118 ◽  
pp. 104186
Author(s):  
Manuel Entfellner ◽  
Pooya Hamdi ◽  
Xiaoyue Wang ◽  
Helmut Wannenmacher ◽  
Florian Amann
Keyword(s):  
High Strength ◽  
Expanded Polystyrene ◽  
Squeezing Ground ◽  
Ground Conditions ◽  
Yielding Support

scholarly journals Tunnel Squeezing Deformation Control and the Use of Yielding Elements in Shotcrete Linings: A Review

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 391
Author(s):  
Xiaomeng Zheng ◽  
Kui Wu ◽  
Zhushan Shao ◽  
Bo Yuan ◽  
Nannan Zhao
Keyword(s):  
High Resistance ◽  
Review Paper ◽  
State Of The Art ◽  
Squeezing Ground ◽  
Deformation Control ◽  
Development History ◽  
Ground Conditions ◽  
Supporting Effect ◽  
Mechanical Performances ◽  
Shotcrete Lining

Shotcrete lining shows high resistance but extremely low deformability. The utilization of yielding elements in shotcrete lining, which leads to the so-called ductile lining, provides a good solution to cope with tunnel squeezing deformations. Although ductile lining exhibits great advantages regarding tunnel squeezing deformation control, little information has been comprehensively and systematically available for its mechanism and design. This is a review paper for the purpose of summarizing the development history and discussing the state of the art of ductile lining. It begins by providing a brief introduction of ductile lining and an explanation of the importance of studying this issue. A following summary of supporting mechanism and benefits of ductile lining used in tunnels excavated in squeezing ground conditions is provided. Then, it summarizes the four main types of yielding elements applied in shotcrete lining and introduces their basic structures and mechanical performances. The influences of parameters of yielding elements on the supporting effect are discussed and the design methods for ductile lining are reviewed as well. Furthermore, recommendations for further research in ductile lining are proposed. Finally, a brief summary is presented.

scholarly journals Biomaterial obtenido a partir de micelio de hongo (ganoderma lucidum) y residuos agrícolas

2021 ◽  
Vol 2 (3) ◽  
pp. 4663-4681
Author(s):  
Gutiérrez Díaz Evelyn Susel ◽  
Edna María Hernández Domínguez ◽  
Ana Guadalupe Estrada Fernández ◽  
Jorge Álvarez Cervantes ◽  
Leiry Desireth Romo Medellín ◽  
...  
Keyword(s):  
Ganoderma Lucidum ◽  
High Strength ◽  
Average Density ◽  
Expanded Polystyrene ◽  
Industrial Wastes ◽  
Walnut Shell ◽  
Maximum Deformation ◽  
Agroindustrial Waste ◽  
Bacteria And Fungi ◽  
Plant Sources

RESUMEN Actualmente la gran cantidad de residuos orgánicos e inorgánicos que se generan en el mundo se están convirtiendo en un problema ambiental. Aunque existen diversas investigaciones para su confinamiento, tratamiento o aprovechamiento, queda mucho por investigar. Desde hace aproximadamente una década, se han desarrollado biomateriales, los cuales son obtenidos a partir de biopolímeros de fuentes vegetales, residuos agroindustriales, así como de bacterias y hongos. El objetivo de la presente investigación es el diseño de un biomaterial a través de la propagación micelial del hongo Ganoderma lucidum, crecido sobre cáscara de nuez y aserrín de roble, ambos residuos agroindustriales. Se formularon cinco sustratos distintos, variando las proporciones de cáscara de nuez (CN) y aserrín (AS) los cuales se describen a continuación; TI-CN100:AS0, TII-CN25:AS75, TIII-CN50:AS50, TIV-CN75:AS25 y TV-CN0:AS100. Después de 30 días de incubación (26° C, y una humedad relativa del 70 al 80%), el TI-CN100:AS0, permitió un desarrollo micelial del hongo Ganoderma lucidum. El biomaterial obtenido presentó un aspecto aterciopelado blanquecino con una estructura similar a una espuma. La prueba de compresión reveló que el biomaterial tiene alta resistencia a 0.392 MPa, con un porcentaje de deformación máximo de 26%. Además, presentó una densidad media de 0.511 ± 0.169 g/cm-3. En general, el biomaterial de estudio se encuentra dentro de los parámetros establecidos para las espumas a base de micelio elaboradas recientemente. Por lo tanto, es un candidato para reemplazar el poliestireno expandido, sin embargo, se requiere una caracterización más amplia, así como estandarización del proceso.   ABSTRACT Currently, the large amount of organic and inorganic wastes generated in the world is becoming an environmental problem. Although there are several researches for their confinement, treatment or utilization, there is still a lot of research to be done. For about a decade, biomaterials have been developed, which are obtained from biopolymers from plant sources, agroindustrial waste, as well as from bacteria and fungi. The objective of the present research is the design of a biomaterial through mycelial propagation of the fungus Ganoderma lucidum, grown on walnut shells and oak sawdust, both agro-industrial wastes. Five different substrates were formulated, varying the proportions of walnut shell (CN) and sawdust (AS) which are described below; TI-CN100:AS0, TII-CN25:AS75, TIII-CN50:AS50, TIV-CN75:AS25 and TV-CN0:AS100. After 30 days of incubation (26°C, and a relative humidity of 70 to 80%), the TI-CN100:AS0 allowed mycelial development of the fungus Ganoderma lucidum. The biomaterial obtained presented a whitish velvety appearance with a foam-like structure. The compression test revealed that the biomaterial has high strength at 0.392 MPa, with a maximum deformation percentage of 26%. In addition, it presented an average density of 0.511 ± 0.169 g/cm-3. Overall, the study biomaterial is within the established parameters for recently developed mycelium-based foams. Therefore, it is a candidate to replace expanded polystyrene, however, further characterization and standardization of the process is required.

Geotechnical risk management approach for TBM tunnelling in squeezing ground conditions

2016 ◽  
Vol 57 ◽  
pp. 201-210 ◽  
Author(s):  
Nicholas Swannell ◽  
Michael Palmer ◽  
Giovanni Barla ◽  
Marco Barla
Keyword(s):  
Risk Management ◽  
Management Approach ◽  
Squeezing Ground ◽  
Ground Conditions ◽  
Geotechnical Risk
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