Definition : Environmental geotechnique is a systematic, scientific way of protecting environment, human and animal life or wild life form damage due to natural disaster, man made projects / activities.
It is a civil engineering discipline that is concerned with building on, in, or with soil and rock. Geotechnical engineers design dams, embankments, cuts, foundations, retaining walls, anchors, tunnels, and all other structures directly interacting with the subsoil, both onshore and offshore.
Ground Engineering is a fundamental component of all civil engineering projects and relates to the provision of complete solutions for ground-related infrastructure, ranging from ground investigation through laboratory testing, design of underground infrastructure and provision of specialist construction supervision.
Disposal of waste generated by people and industrial processes is an important issue in our society. If this waste is not managed in a safe and reliable manner, then human health and the environment are at risk. Waste containment facilities like landfills are one of the most commonly used means for waste disposal.
What are the criteria for the structural stability of landfilled municipal solid waste, for example, especially when the material is undergoing chemical and biological degradation over many years? Sewage sludges, industrially contaminated soils and stabilised waste all have their own geotechnical characteristics when considering disposal and management
where the natural environment is concerned, hydrology is frequently the driver of contaminant movement as well as structural instability problems.
The influence of climate change on many of these environmental issues presents significant challenges to both hydrological and geotechnical analyses to which Environmental Geotechnics as a discipline has much to contribute.
The remedial actions can be classified into four broad categories, which include engineering based and process-based methods6 (a) removal (b) containment (c) rehabilitation (d) treatment.
The main objectives of environmental geotechnics are:
The creation of better environment
The prevention of environmental risks to human activities.
The prevention of dangers to human life caused by natural hazards.
Measures to create better environment and prevention of loss:
- Erosion Control
- Flood control
- Slope protection
- Land sliding prevention
- Municipal / Hazardous waste management
- Water resources management
- Control of natural disaster
- Recycling/reuse of waste
Erosion / Flood control : Use of geosynthetics like Geobag, Geotubes, Gabions helps in control of these natural disaster.
Slope protection: Geotextile, Geocells are used to stabilize the slope.
Land sliding : Land sliding can be prevented using geosynthetics and metal nets.
Waste management –Landfilling : Municipal waste /hazardous waste is dumped in excavated land ( over geosynthetics like nonwoven geotextile, geomembrane and geosynthetic clay liner ) and then covered with geosynthetics with leachate collection and gas collection system. Gas generated from waste can be utilized for heating or cooking. Leachate (contaminated water) is purified and utilized for industrial applications.
The construction of liners, floors, walls and cover (capping) systems that adequately limit the spread of pollutants and the infiltration of surface water . The containment, collection and removal of leakage from landfills . The control, collection, and removal or use of landfill gases . The maintenance of landfill stability . Monitoring to ensure that the necessary long term performance is being achieved.
◼ Geochemistry and geohydrology;
◼ Soil and rock physics, biological processes in soil, soil-atmosphere interaction;
◼ Waste management, utilization of wastes, multiphase science, landslide wasting, soil and water conservation;
◼ The impact of climatic changes on geo-environmental, geothermal/ground-source energy, carbon sequestration, oil and gas extraction techniques,
◼ Uncertainty, reliability and risk, monitoring and forensic geotechnics
Waste management should be based on an environmental geotechnical approach. Large amounts of waste are generated from industry and human activity. The hierarchy in management is waste minimisation, proper treatment, reuse/recycling and energy recovery. Natural resources should be preserved and the need for landfill minimised.
The objective of any risk assessment is to determine the risk to groundwater, other aquatic systems and ecosystems through discharge of substances from a landfill.
Water resources : Water ways, artificial reservoirs, canals are created also using geosynthetics.
Control of natural disasters : Disasters like earthquake, Tsunami, Land sliding etc can be controlled to some extent to save lives and property.
Re-use of waste :
Surplus soil and waste slurry, Waste concrete and waste rock powder ,Coal ash ,Iron, steel, and other slags, Mining waste , Municipal solid waste incinerated ash (MSWIA) , Sewage sludge incinerated ash ,Paper sludge , Waste tyres , Waste plastics and other similar materials When using recycled materials, such as industrial and municipal wastes and surplus soils, the potential for pollution must be assessed under the environment of a given application.
Measures for Better Environment
Land filling of MSW Recycling of hazardous waste Composting / Bio Gas generation
Slope Protection, Rock Fall Prevention, Metal Gabion walls
- VARIOUS GEOSYNTHETIC PRODUCTS USED IN PREVENTING ENVIRONMENTAL LOSS
Geobags Geotubes Geomattress
Evaluation and certifying the products: Geosynthetics which are used in various applications need to be evaluated at laboratory level and on site. Index test, performance tests are carried out and certified by accredited laboratory before putting them in to use.
Following Properties need to evaluate.
- Mechanical properties
- Hydraulic properties
- Durability properties
- Endurance properties