Development Of Self-leveling Backfill Material And Its Application In The Check Well

It is found that the check well and its surrounding road surfaces are affected by trafficload, and the manhole covers’ surrounding sides ranging from10cm to30cm tend to bedestroyed the earliest. The quality diseases happen easily such as cyclic cracking, pit slot,subsidence, fracture and ruin, overlarge elevation difference between check well and andits surrounding road surfaces. These diseases are mainly caused because the backfillmaterials of the check well’ surrounding road surfaces hasn’t met the requirements ofcompactness. To improve the uncompacted quality of the traditional backfill materials, aself-leveling backfill material is to be developed in this paper, with properties of self-filling,self-leveling and self-compaction.First, systematic mix-ratio tests were conducted with the self-leveling backfillmaterials. The effects of the ratio of the furnace bottom ash and fly ash and cement contenton the self-leveling backfill materials’ segregation, bleeding, subsidence, strength andshrinkage deformation were explored. The ratio proportions of the self-leveling backfillmaterials were determined initially as: cement content from0.7%to1.0%, the ratio of thefurnace bottom ash and fly ash around2.Through the orthogonal test, the ratio proportions were improved, and the effects ofthe three elements namely the ratio of the furnace bottom ash and fly ash, cement content,and addition of modifier A211on the self-leveling backfill materials’ segregation, bleeding,subsidence, initial setting time,strength and shrinkage deformation were researched. Thebest ratio proportion was determined as the ratio of the furnace bottom ash and fly ash1,cement content0.09, and addition of modifier A21115%.Through the finite element software MARC, the check well and its surrounding roadsurfaces’ subsidence was conducted in finite element simulation. The effects of differentbackfill materials on the check well and its surrounding road surfaces were analyzed. Thesimulation results show that the self-leveling backfill materials can effectively improve thesubsidence of the check well’s surrounding road surfaces.The self-leveling backfill materials sudied in this paper can not only satisfy therequirements of the check well’s backfill materials, and also improve the diseases caused bythe backfill materials’ disqualification of the check well’s surrounding road surfaces, whichis significant to protect the urban environment.