Rapid Consolidation Behavior of Dredged Clays at High Water Content

2011 ◽  
Vol 368-373 ◽  
pp. 2966-2970
Author(s):  
Yu Peng Cao ◽  
Jian Wen Ding ◽  
Xia Bian ◽  
Feng Ji ◽  
Gui Zhong Xu
Keyword(s):  
Large Scale ◽  
High Water ◽  
Laboratory Model ◽  
High Water Content ◽  
Vertical Drains ◽  
Drainage Rate ◽  
Horizontal Drains ◽  
The Stability ◽  
Stability Time ◽  
Consolidation Behavior

Consolidation of dredged clays with a system of horizontal and vertical drains is considered. Horizontal drains in the system are made of sand layers, while vertical drains are plastic vertical drains (PVD). Laboratory model tests are performed to study the rapid consolidation behavior of layered clay-sand and clay with PVD. Special cares are given to settlement and the drainage rate of dredged clays with radial and vertical drain system. Numerical analysis is also used to identify the stability time of consolidation, and to verify which method is better suitable for handling large-scale dredged clays.

Characterization of a smear zone around vertical drains by large-scale laboratory tests

2000 ◽  
Vol 37 (6) ◽  
pp. 1265-1271 ◽  
Author(s):  
J S Sharma ◽  
D Xiao
Keyword(s):  
Large Scale ◽  
Soft Clay ◽  
Excess Pore Pressure ◽  
Laboratory Model ◽  
Clay Layer ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Undisturbed Samples ◽  
Oedometer Tests ◽  
Excess Pore

Installation of prefabricated vertical drains using a mandrel causes disturbance of clay surrounding the drain, resulting in a "smear" zone of reduced permeability. In this paper, an attempt is made to characterize the smear zone using large-scale laboratory model tests. Two tests, simulating the cases of "no smear" and "with smear," were conducted. Excess pore-water pressures were monitored at seven different locations along the radial direction. In addition, undisturbed samples were collected at various locations in the clay layer for conducting oedometer tests. The distribution of excess pore pressure due to drain installation gave a clear indication of the extent of the smear zone. The effect of reconsolidation on the properties of clay was found to be much greater than that of the remoulding of the clay. The extent of the smear zone was also confirmed from the change in permeability of the clay layer in the smear zone obtained from oedometer tests. The radius of the smear zone is about four times that of the mandrel, and the horizontal permeability of the clay layer in the smear zone is approximately 1.3 times smaller than that in the intact zone.Key words: consolidation, permeability, smear zone, soft clay, vertical drains.

scholarly journals UNDERGROUND AIR DUCT TO CONTROL RISING MOISTURE IN HISTORIC BUILDINGS: IMPROVED DESIGN AND ITS DRYING EFFICIENCY

2017 ◽  
Vol 57 (5) ◽  
pp. 331 ◽  
Author(s):  
Jiří Pazderka ◽  
Eva Hájková ◽  
Martin Jiránek
Keyword(s):  
Experimental Study ◽  
Reference Sample ◽  
Ground Surface ◽  
High Water ◽  
Laboratory Model ◽  
High Water Content ◽  
Technical Solution ◽  
Historic Buildings ◽  
Concrete Blocks ◽  
Drying Efficiency

The underground air ducts along peripheral walls of a building are a remediation method, which principle is to enable an air flow along the moist building structure’s surface to allow a sufficient evaporation of moisture from the structure. This measure reduces the water transport (rising moisture) into the higher parts of the wall where the high water content in masonry is undesirable. Presently, underground air ducts are designed as masonry structures, which durability in contact with ground moisture is limited. The article describes a new design of an underground air duct, which is based on specially shaped concrete blocks (without wet processes, because the blocks are completely precast). The air duct from concrete blocks is situated completely below the ground surface (exterior) or below the floor (interior). Thanks to this, the system is invisible and does not disturb the authentic look of rehabilitated historic buildings. The efficiency of the air duct technical solution was verified by the results of tests (based on the measured moisture values) conducted on a laboratory model. The experimental study showed that the moisture in the masonry equipped with the presented underground air duct had decreased considerably compared to the reference sample, namely by 43 % on average. The experimental study was numerically validated through numerical simulations performed with the program WUFI 2D.

Environmental impacts of a large-scale incinerator with mixed MSW of high water content from a LCA perspective

2015 ◽  
Vol 30 ◽  
pp. 173-179 ◽  
Author(s):  
Ziyang Lou ◽  
Bernd Bilitewski ◽  
Nanwen Zhu ◽  
Xiaoli Chai ◽  
Bing Li ◽  
...  
Keyword(s):  
Water Content ◽  
Environmental Impacts ◽  
Large Scale ◽  
High Water ◽  
High Water Content

Fiber Filled Hybrid Hydrogel for Bio-Manufacturing

2020 ◽  
pp. 1-38
Author(s):  
MD Habib ◽  
Bashir Khoda
Keyword(s):  
Cell Viability ◽  
Large Scale ◽  
Three Dimensional ◽  
High Water ◽  
Solid Content ◽  
Design Stage ◽  
High Water Content ◽  
Cellulose Derivatives ◽  
Hybrid Hydrogel ◽  
Low Cytotoxicity

Abstract The extrusion based three-dimensional (3D) bio-printing deposits cell-laden bio-ink with high spatial resolution and may offer living tissue regeneration. Due to the biocompatibility, very low cytotoxicity, and high-water content, natural hydrogels are commonly considered as the cell-laden bio-ink for scaffold fabrication. However, due to the low mechanical integrity, a large-scale scaffold (> 10 layers) with intricate architecture is a challenge. In this paper, we developed and characterize a novel bio-ink consisting of alginate, CMC, and TO-NFC for bio-printing applications. The potential of cellulose derivatives in terms of rheological property to satisfy scaffold architecture and cell viability is explored with a relatively small amount of solid content (<5%). By combining alginate, CMC, and TO-NFC as a hybrid hydrogel, we design to overcome their individual challenges as bio-ink. At the design stage, we have considered two main characteristics, printability and shape fidelity with quantitative indices. We studied the rheological characteristics for determining the suitable composition for extrusion bio-printing. Our investigation suggests an optimal material composition that can print 42 layers and a 9 mm tall scaffold structure. The proposed hybrid hydrogel is used to prepare bio-ink encapsulating cells and cell viability is measured as 90% after 10 days of incubation.

scholarly journals Stability of cactus-pear powder during storage

2016 ◽  
Vol 20 (2) ◽  
pp. 169-173
Author(s):  
Plúvia O. Galdino ◽  
Rossana M. F. de Figueirêdo ◽  
Alexandre J. de M. Queiroz ◽  
Pablícia O. Galdino ◽  
Tâmila K. da S. Fernandes
Keyword(s):  
Water Content ◽  
Water Activity ◽  
Reducing Sugars ◽  
Titratable Acidity ◽  
High Water ◽  
Soluble Solids ◽  
High Water Content ◽  
Cactus Pear ◽  
Total Titratable Acidity ◽  
The Stability

ABSTRACT The stability of cactus-pear powder, obtained by the process of spray drying for 40 days, was evaluated under controlled conditions of relative air humidity (83%) and temperature (25 and 40 °C). The whole pulp was characterized with regard to its physico-chemical parameters: pH, total titratable acidity, soluble solids, water content, total solids, ashes, reducing sugars, total sugars, non-reducing sugars, luminosity, redness, yellowness and water activity. The stored samples in powder were evaluated every 10 days for water content, water activity, total titratable acidity and color (luminosity, redness and yellowness). The whole pulp was slightly acidic and perishable, due to the high water content. During storage, the packages did not prevent water absorption, thus increasing water content and, consequently, water activity. Yellowness oscillated along the storage time, but the predominance of the yellow color was not affected.

scholarly journals Properties and Application of Backfill Materials in Coal Mines in China

Minerals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 53 ◽  
Author(s):  
Jixiong Zhang ◽  
Meng Li ◽  
Abbas Taheri ◽  
Weiqing Zhang ◽  
Zhongya Wu ◽  
...  
Keyword(s):  
Large Scale ◽  
Coal Mines ◽  
High Stress ◽  
High Water ◽  
High Water Content ◽  
Environmental Aspects ◽  
Coal Resources ◽  
Mining Areas ◽  
Mining Depth ◽  
Backfill Materials

Coal is the basic resource underpinning energy generation in China, however, constant, large-scale mining of coal results in many problems such as ecological destruction of mining areas. As a result, backfilling of solid waste underground is proposed to control strata and surface subsidence and to protect the environment. At present, these materials, such as granular material, cemented material and high-water-content materials are mainly used for backfilling. This study summarised the types of backfill materials that are used in coal mines in China along with the backfilling process. Moreover, distribution and characteristics of mines backfilled with these backfill materials were obtained and analysed. Considering the socio-environmental aspects that affect backfilling, this research proposed a guideline for the selection of backfill materials and then analysed specific engineering cases of three backfill materials. In addition, the future development of backfill materials was discussed. With extensive extraction of shallow coal resources in China and, therefore, rapid depletion of coal resources in eastern regions of China, coal mining depth is increasing significantly. As a result, it is required to investigate new backfill materials suited for the deep high-stress environment.

A Discussion of the Stability of Foundation Pit or Slope with Soft Interlayer or with Back Berm

2014 ◽  
Vol 1065-1069 ◽  
pp. 96-99
Author(s):  
Hai Ying Hu ◽  
Xiao Wen Zhou ◽  
Zhi Xing Huang
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
High Water ◽  
High Water Content ◽  
Sliding Surface ◽  
Foundation Pit ◽  
Soft Interlayer ◽  
The Difference ◽  
The Stability ◽  
Slice Method

The soft soil in Pearl River Delta regions is characterized with high water content, high compressibility and low bearing capacity. Therefore, when building the structures on such foundation, it’s necessary to pay attention to the deformation and stability. The projects' practice shows that, when analyzing the stability on foundation pit or slope with soft interlayer, it should not only calculate the overall stability of the slope, but also calculate the stability or bearing capacity of the foundation. Although sometimes the stability of the slope meets the requirements, it doesn’t means that the bearing capacity of the foundation meets the requirements because of the existence soft interlayer, the limitations of the circle slice method and the difference between the sliding surface and the actual sliding surface.

The Dusty Creek landslide on Mount Cayley, British Columbia

1982 ◽  
Vol 19 (3) ◽  
pp. 524-539 ◽  
Author(s):  
J. J. Clague ◽  
J. G. Souther
Keyword(s):  
British Columbia ◽  
Debris Flows ◽  
Maximum Velocity ◽  
High Water ◽  
High Water Content ◽  
Contributing Factors ◽  
Coast Mountains ◽  
Basement Rocks ◽  
Debris Dams ◽  
The Stability

A large (ca. 5 × 106 m3) landslide occurred on the west flank of Mount Cayley in the southern Coast Mountains of British Columbia in 1963. Failure commenced when a large block of poorly consolidated tuff breccia and columnar-jointed dacite was detached from the subvolcanic basement and slid into the valley of Dusty Creek, a small tributary of Turbid Creek. As the detached block accelerated, it quickly fragmented into an aggregate consisting of angular clasts up to several metres across, partially supported by a matrix of fine comminuted rock material. The landslide debris moved about 1 km down Dusty Creek as a wedge-shaped mass up to 70 m thick, banking up on turns and attaining a maximum velocity of 15–20 m/s. The debris mass thinned as it spread across the broader, flatter valley of Turbid Creek, and was deposited as an irregular blanket with a maximum thickness of 65 m along a 1 km length of this valley. As a result of the landslide, Turbid and Dusty Creeks were blocked, and lakes formed behind the debris. These debris dams were soon overtopped and rapidly breached, causing floods and probably debris flows to sweep down Turbid Creek valley far beyond the terminus of the landslide.From an analysis of the annual rings of slide-damaged trees, it is concluded that the landslide probably occurred in July 1963. Although the largest earthquake of 1963 and a moderately intense rainstorm also occurred during this month, there were much larger earthquakes and storms in this area on many previous occasions, and these did not cause large slope failures. Thus, it appears that the stability of the slope at the head of Dusty Creek gradually deteriorated over a long period of time until a relatively minor event, such as a small earthquake or storm, triggered the failure.The main contributing factors to this landslide are geologic and include the presence of: (1) hydrothermally altered faults and fractures in poorly lithified pyroclastic rocks and in jointed volcanic flows; (2) an outward-sloping unconformity separating the Quaternary volcanic sequence from older basement rocks; and (3) fractured glassy selvages surrounding small intrusions in the base of the volcanic pile.Deposits of one or more landslides that predate the 1963 event also occur in Turbid Creek valley. These older deposits are present over a much larger area than the 1963 slide deposits and probably were emplaced by highly mobile debris flows with high water content.

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