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Introduction
Published in Lin Li, Farshad Amini, Yi Pan, Saiyu Yuan, Bora Cetin, Hydraulics of Levee Overtopping, 2020
Lin Li, Farshad Amini, Yi Pan, Saiyu Yuan, Bora Cetin
An evaluation of the various innovative overtopping protection methods indicates that a cellular confinement system using concrete-filled cells would be applicable for use when rapid, rather expensive, construction is justified and the subsequent rising of the levee is anticipated. Flow velocities in the range of 1.8–3.0 m/s can be handled using this approach. Reinforced grass would have limited application because it would take several months (or years) for the root system to develop and it would be limited (unless more flood-resistant grass and/or additional anchorage is provided) to flow durations less than 2 days. In addition, reinforced grass can handle flow velocities up to 3.8 m/s. Although reinforced grass is generally more economical than conventional engineering materials in capital cost, it can be more expensive to maintain. Soil cement is, in general, cost-competitive for nonsediment-laden flows with velocities up to 7.6 m/s (Perry 1998). For flows with high velocities, three innovative and cost-effective levee-strengthening systems, namely, anchored high-performance turf reinforcement mat (HPTRM), articulated concrete block system (hard-armor products), and roller-compacted concrete (RCC) system may be considered.
Sludge Dewatering
Published in Alice B. Outwater, Reuse of Sludge and Minor Wastewater Residuals, 2020
Concrete slabs that accommodate the tire width of a tractor can be built into the sand drying bed, facilitating tractor operation and reducing the effective surface area of the sand filter. Geotextiles designed to support vehicular traffic over poor soil conditions have been used successfully in sand drying beds. In Florida, the Sarasota County Solid-Waste Operations Division used the cellular confinement system, a geosynthetic material made of high-density polyethylene plastic in a range of 2- to 8-in. cell depths. A cross section of the installation consists of a 2-in. layer of sand laid over the sand-filled cellular confinement system, geonet, and then the gravel bed. Cleaning the sand drying bed requires removing only the top 1 to 2 in. of sand that is directly under the sludge, increasing the life of the drying bed.3
Traditional and innovative methods for physical and chemical remediation of soil contaminated with organic contaminants
Published in Katalin Gruiz, Tamás Meggyes, Éva Fenyvesi, Engineering Tools for Environmental Risk Management – 4, 2019
É. Fenyvesi, K. Gruiz, E. Morillo, J. Villaverde
There is a plethora of mechanical soil immobilization methods: retaining walls and terraces, geotextile application, other cover by net from plant material (pl. coco or palm), spikes, vetiver plant (plant with extremely long roots to keep firm the upper layer of the soil), etc. Some products marketed for temporary and permanent soil erosion protection are listed here: Aspen Excelsior Logs, biodegradable (Western Excelsior, 2018);Erosion control blankets (ECB) made of straw and/or coconut, biodegradable (ECB Verdyol, 2018);Turf reinforcement mats (TRMs), synthetic, non-biodegradable, stabilized against UV degradation, provide long-term erosion resistance (Contech, 2018);High performance turf reinforcement mats (HPTRMs) for slope control (Propex, 2018a);ArmorMax: HPTRMs and engineered earth anchors (Propex, 2018b);Terra-Tubes fiber filtration tubes (FFTs) engineered composites of wood fibers, man-made fibers and performance-enhancing polymers (Profiles, 2018a);Geocell cellular confinement system, an engineered, high-strength network of interconnected cells for stabilizing soil against erosion (Presto, 2018);Gabion baskets, Reno mattresses, and Terramesh, hexagonal woven galvanized steel wire mesh compacted baskets filled with stone or soil (Geo-Solutions, 2018a);Geotube® Dewatering Technology (Geo-Solutions, 2018b);HydroTurf™ (AOF, 2018a);Native Grass Sod (Geo-Solutions, 2018c);Flexterra Flexible Growth Medium (FGM) (AOF, 2018b);ProMatrix™ Engineered Fiber Matrix (EFM) (Profiles, 2018b);Sod Staples for proper anchoring the erosion products (blankets, etc.).
Development of a simplified design approach for shallow ballasted track forms with geocells reinforced sub-ballast
Published in International Journal of Rail Transportation, 2022
Various research studies [7,8] have investigated the reinforcing effect of geocells via means of static lab testing. These research studies have identified that there are three main mechanisms that explain the reinforcing effect of geocells, which ultimately improve load distribution on the subgrade. These mechanisms are illustrated in Figure 2 and are described as follows: Vertical cellular confinement: This is generated due to the friction between the infill material with the inner walls of the geocells. The magnitude of the friction is a function of the geocell inner wall, surface texture, and infill material friction angle [9].Lateral cellular confinement: This is generated due to the geocell ability to limit lateral movement inside each cell, which generate hoop stresses around the cells and in turn provide a stiffer mattress on the subgrade soil.Tension membrane effect: This is due to the vertical applied loads and the resulting tension in the geocell skeleton.