Principles & Techniques of Bioengineering for Civil Engineers - VIVEK DHAKAL

Principles & Techniques of Bioengineering for Civil Engineers

In a broader sense, Bioengineering is the use of life science & engineering to solve human life problems. Here, in this article, we are using the term bioengineering in the context of civil engineering & it basically refers to soil bioengineering. So, Bioengineering can be defined as the use of vegetative measures & small civil engineering structures in order to reduce the shallow seated instability. The living plants or non-living plant materials are used alone or in conjunction with small civil engineering structures for slope stabilization & erosion control. It utilizes locally available resources & is a cost-effective method.

Principles of Bioengineering

Initially, stability is obtained from the small civil engineering structures. The strength of those structures decreases gradually. After the handover point, stability is derived from the vegetative measures. This can be depicted from the graph shown below:
Principles of Soil Bioengineering

Functions of Bioengineering

Engineering functions performed by vegetation on a slope are as follows:
  • Catch
  • Armor
  • Reinforce
  • Anchor
  • Support
  • Drain

Advantages of Bioengineering

  • Immediate slope stabilization & erosion control
  • Utilization of locally available resources (local tools, local manpower, local materials)
  • It is a cost-effective method
  • No need for frequent maintenance
  • It also provides an opportunity for wildlife habitat
  • It also improves the aesthetic beauty of the site

Commonly Used Techniques of Bioengineering

  • Fascine: Bundle of live branches laid in shallow trenches
  • Palisade: Woody cuttings planted across the slope.
  • Wattling: Fence made out of vegetative materials.
  • Bamboo Planting: Planting of bamboo for soil conservation
  • Grass Planting: Planting of grass across the slope
  • Brush Layering: Layers of woody cuttings planted in line following the contour
  • RipRap: Stone pitching with vegetation interplanted between them
  • Retaining Wall: Wall built to resist the pressure of earth filling or backing
    • Toe Wall
    • Breast Wall or Revetment Wall
  • Check Dam: Dams constructed across the gullies to retard the flow
  • Gabion Wall: Walls made up of gabion wire filled with stones
  • Stone Masonry: Masonry construction using stones & mortar 
  • Jute Netting: Protecting the slope with standard jute mesh
  • Rock Netting: Wire mesh of reliable material used to control the rockfall
  • Rock Bolting: Reinforcement of rock slope by inserting steel bars
  • French Drain: Subsurface drainage channel filled with aggregates