Pilot Study Of Qinhuangdao-shenyang Passenger Dedicated Line Roadbed Construction Technology And Quality Detection Methods

Qinhuangdao-Shenyang Dedicated Passenger Traffic Railway Line isthe first new railway at the velocity of 200km/h in our country. There isnot any domestic experience in engineering technology. Through thestudy on the construction technique of rank mixed detritus of subgradetop layer, general filling materials and improvement soil of silty clay,the influencing factors of compression effect of roadbed filling havebeen recognized and understood. These conclusions can be used in thefuture railway construction of high speed railway and dedicatedpassenger traffic railway line. The main conclusions are as follow.The influencing factors of compaction effect of roadbed filling arevery complicated, mainly including the filling properties, compactionmachines, the mode and times of compaction, virtual height, watercontent, and so on.There are different compaction effects for different filling materials,even though the same compaction machines, virtual height and times ofcompaction are adopted. Among these filling properties, the filling rankis the main factor that influences the compaction effect. For fine granularsoil, the strength value of cohesion (c) and angle of internal friction (φ)is another factor. It is the different interior properties of filling that comeabout the different compaction effect of various filling. Under the sameconditions of the soil type, water content and virtual height, the morepower the compaction machine has, the more density filling has. In theprocess of filling compaction, allocation of compaction machines andaccommodation of compaction modes should be in harmony with oneanother with the filling variation. According to the filling properties, thepower of compaction machines and the desirable compaction degree,water content in the process of compaction construction have to be takeninto account to attain the best compaction effect. From bothconsideration, cost and compaction effect, there is the most suitablecompaction thickness for a sort of filling material and compactionmachine. The inter-granular porosity is supposed to as controlling parameter offilling degree in place of the porosity which is demanded to use in norm.The K₃₀ value, which is used as the controlling parameter of the fillingstrength, is reasonable for the fine filling. Because different coarse fillinghas different ability of reaching the same K₃₀ value, it isn't appropriate toevaluate the quality of all coarse filling with one K₃₀ value. The K₃₀value also varies with measuring time.