Hi Civiant!
Want to know about this new world?
The world is exploring construction and infrastructure as the limits to sky. Everyone here has witnessed the art of civil engineer in the form of various sculptures, buildings, industrial projects, etc. But I think these people are now more inspired by rabbit to transform a burrow to a next level! These burrows are called as underground civil engineering macro and mass transit systems, underground storages, critical infrastructures, research centres and pretty much anything to go underground. Let’s see in this article of how much known is this under-world to us.
- Why underground engineering?
We always seek for comfort and safety utmost, so they protect from external factors or elements and even enemies! This provided wide number of solutions for soldiers to save themselves at the critical points. Also, underground homes are now liked by thousands of people in Europe and America. Energy efficient structure is the most highlighting advantage in this category. All theses are built to drawing and specifications. The drainage systems through underground have vital role and convenient to discharge the waste water by gravity drainage systems in effective budget.
- Subterranean – are underground structures, both natural (such as caves) and human-made (such as mines). In recent years, many companies have relied on subterranean architecture to give their establishment a unique look and design. These commercial buildings may lack foot traffic but they offer a unique experience that is unavailable above ground. Some of these subterranean structures include tunnelled sneaker stores, submerged espresso bars and even underground museums.
- An underground way – Yay it’s a Tunnel –
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end. A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers. Other uses include routing power or telecommunication cables, some are to permit wildlife such as European badgers to cross highways. In the United Kingdom, a pedestrian tunnel or other underpass beneath a road is called a underpass subway. In the United States that term now means an underground rapid transit system. The central part of a rapid transit network is usually built in tunnels. Rail station platforms may be connected by pedestrian tunnels or by foot bridges.
To help employers protect the safety and health of underground construction workers, the Occupational Safety and Health Administration (OSHA) has prepared a number of guidance documents, including the underground construction regulations, found in Part 1926, section 800 of Title 29 of the Code of Federal Regulations (29 CFR 1926.800).
- Underground in Mahabharata? Really?
You might be knowing about Lakshagriha! If not, then please read forward… The famous Lakshagriha escape route planned by Pandavas was through secret tunnel under the lakshagriha. Many more tunnels have been found in the old forts and palaces which were used as secret escape routes. So, that’s how in India construction of tunnels in the form of underground passages and water carrying conduits dates back to Mahabharata era!!!
Okay now let’s come in modern era… the tunnelling and underground works constitute a major portion of development of rail tunnels, road tunnels, hydro power, mining, strategic oils reserves, water supply & sewerage, coal mines, nuclear power projects and urban area metro rail network as well as strategic secret escape routes etc.
- Everything nice doesn’t seems real. Know the problems faced –
The biggest interface encountered is the soil or geotechnical information and its suitability for such exploration. Stability of soil needs to checked for the design life of the structure with all critical or worst cases. The geological and geotechnical investigation program is required be adequately accomplished in order to provide realistic information for economic and safe design and construction of the underground structures – said by former executive director head of NHPC.
The tunnels which are located in Himalayas are faced with complex geological conditions and then contractual disputed override and the work gets affected. Even EPC contracts and turnkey contracts enter into unending disputes contributing to major cost & time overruns. Some ground complications are mentioned below :
- Squeezing ground conditions
- Upheavals
- Tectonic stresses
- Popping
- Rock bursting
- High temperature gradient
- Heavy ingress of water during execution
- Existence of large shear zones
- Flowing ground conditions
- Abrupt change in strata conditions
- Low cover zones or very high cover/ overburden
- Emission of methane and other gases, etc.
The problems especially while executing hydropower projects in complex Himalayan region may be regarded as challenge and opportunity for generating new knowledge base and thereby increasing self-reliance, particularly in tunnelling and underground works.
The aim should be to obtain as complete information of the subsurface geological conditions to arrive at a techno-economic evaluation of the project. At times, situation might demand further investigations, therefore, time and quantum of site investigation should commensurate with the size and complexity of the project.