The basic way to bury pipelines into ground in the municipal projects is: excavating a trench firstly

and throwing away the excavated soils as wastes; backfilling the expensive lime-ash soil into the trench after the pipelines are placed properly; tamping foundation and laying asphalt or concrete pavements. In consideration of recycling the excavated soils and reducing the use of lime-ash soil

soilbag technique is suggested in urban trench backfills so as to cut down the project costs. The mechanism of soilbag technique is briefly elucidated herein; and several field tests such as plate loading test

falling-weight deflection and vibration response measurements are then carried out respectively to evaluate the benefits of a soilbag-trench

with the strong support of the Rain and Sewage Diversion Project in Nanjing. The test results show that soilbag technique performances superbly in improving the bearing capacity of subgrade

decreasing the settlement of roadbed as well as in reducing and isolating the traffic-induced vibrations

compared with the common backfill scheme. It is also proved that backfilling the trench with soilbags is a new green

environment-friendly and economical approach for the municipal projects as a result of avoiding the removal of discarded soils and controlling the pollution of raised dust.