TOKYO GAS TOP > Technical development > Toward the safe and secure supply of energy > Temporary backfill "Eco-balls "

Temporary backfill "Eco-balls"

Eco-balls are a temporary backfill for use after test excavations. They reduce the surplus soil from excavation, and shorten construction time on a road.



In most cases, gas utility construction work takes the form of a test excavation followed by the actual construction work, with two excavations and backfills being carried out in the same place in a short period (approximately one week). In addition to the large volumes of excavated soil and scrap road material produced, the environmental burden of the CO2, NOx, and PM (particulate material) emissions from the dump trucks used to remove these materials has also been a problem. Eco-balls are used as temporary backfill in place of soil or sand in a location that has been excavated once in preparation for actual excavation work, reducing the creation of excavated soil, and decreasing gas emissions from dump trucks.


Outline and user guide of Eco-balls

Eco-balls are polypropylene balls with a diameter of 5 cm (see figure Photo of Eco-balls), bagged in units of several hundred for use (see figure Photo of packed state of Eco-balls).
Photo of Eco-balls Photo of packed state of Eco-balls

When performing temporary backfill, eco-balls are first used as refill in place of soil or sand (see figure Example showing the use of Eco-balls), after which construction with base material and asphalt takes place.
Example showing the use of Eco-balls



  • Reduction in purchase of backfill as well as creation of excavated soil
  • Reduced gas emissions due to decreased dump truck movement cycles
  • Reduction of noise/vibration through shortened backfill and re-excavation times
  • Avoidance of traffic congestion by reducing the length of time that the road is worked on



Our affiliated companies are trying to spread the use of Eco-balls for other gas, water, and electricity businesses. Additionally, rental agencies have begun rental of Eco-balls.

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