Study With The Stone Soil—rock Fill High Subgrade Compaction Process

With the further development of China's highway network,the highway network system in various provinces and cities is also maturing and improving.However,in the process of construction,the topographic and geological conditions and climatic conditions are not the same.Although the general subgrade will settle,but high fill subgrade may be more serious,may cause bridge jump,subgrade settlement,uneven pavement cracks and other quality diseases,which directly affect the quality of the highway project.Therefore,we need to well control the compaction degree of subgrade and one of the key factors is to check the compaction quality of subgrade in the construction process.At present a lot of filling roadbed are inevitably used earth-rock mixed filler as subgrade filling,but to the more stone soil-rock contained fill roadbed engineering,its packing classification,the compaction process,subgrade compaction quality control standards,etc.,also didn't have a set of relatively complete and system evaluation system,and no more perfect and normative guidelines for design and construction,the existing research is more established on the basis of fine grained soils.In view of this,relying on the construction process of high fill roadbed with soil and rock mixed in Xingtai section of Taihang expressway,the characteristics of one roadbed filled with granite gneiss and non-viscous soil with different weathering degree and the other roadbed filled with large-particle size block stone and silty clay mixed fill roadbed are analyzed.Mainly using continuous compaction control technology VCV and dynamic deformation modulus EVD,etc as a detection method for the compaction quality test,by field data analysis combined with auxiliary particle discrete element simulation,to study with the stone soil-rock fill high fill subgrade compaction process and impact conditions,has made the following main research results:(1)The compressive strength of large-particle size stone in two different kinds of fillers in two working points was obtained through point load experiment analysis,and the impact of the roller on the rolling process of the two kinds of fillers was analyzed to obtain their strength.The continuous compaction of the roller under different working conditions on site and the dynamic deformation modulus test was carried out immediately after the compaction.For containing a big size stone soil-rock fill subgrade compaction quality tests,VCV index is through the vibration of the roller wheel vibration acceleration to indirectly reflects several fixed point characteristics of surface and shallow layer subgrade bearing capacity of subgrade reclamation,therefore EVD index compared with VCV index discrete degree bigger,VCV index can better reflect the compaction process of medium pressure real situation.In terms of the compaction uniformity of roadbed and the correlation between the two indexes,the non-viscous soil and rock mixed packing is better than that of the clay soil and rock mixed packing,and three factors affecting the compaction process are obtained under different working conditions of two working points: the tonnage of the roller,the thickness of the filling layer,and the number of times of rolling.(2)The compaction process of soil-stone mixed packing was simulated by particle flow program PFC3 D,and the porosity of the packing particles was used to reflect the actual compaction quality.It is concluded that the priority of the influence of porosity is the content of large block stone>loading plate quality >loose pavement thickness > small block stone content.Therefore,it is necessary to control the content of blocks and stones in the packing,reduce the loose thickness of the packing,and appropriately increase the tonnage of the compaction machine to achieve a better compaction degree,which is consistent with the actual situation on site.