Structural Design And Analysis On Rotary-drill With Pipes Used For Grouting Reinforcement Of Soil Subgrade

By2020, the mileage of China’s nonballasted track of high-speed railway willreach12000kilometre, Rail transit construction accounts for fifteen to twenty of thetotal mileage of subgrade engineering, embankment settlement will face a lot ofdrilling grouting reinforcement work after three to five years’ operation. Conventionalwet drilling methods will change the traits of subgrade, and they should not be used.Meanwhile air compressors and processing equipments of drilling powdery cuttingsare too large and complexed, and they are very inconvenient for transportation onunstructured road. And more disadvantages, such as high cost, time-consuming,inefficience, environment pollution caused by soil powder. Based on all the aboveproblems, this paper develops a rotary drill with pipes which is suitable for simpleengineering machinery and used for small diameter drillings according to the theoryof cutting, the finite element theory, and also combined with field tests. We mainlyhave done the following work:(1) Referring to the functional requirements and technical specifications ofdrilling grouting reinforcement work and the morphological matrix, this paper putsforward a rotary drill with pipes. It proposes the idea that the reaming dril is in thefront of the center drill;(2) According to the overall power requirements and the grouting drill subgrade conditions, this paper places three uniform petals circumferentially. It re-ams while the power head rotates positively. Three flaps stay against each other and they have a sufficient rigidity, so that they won’t move even if encountering collisions. It closes up while the power headrotates oppositely, so the drillcould move in the pipes;(3) According to the overall power requirements and the grouting drill subgradeconditions, this paper studys rotary drilling with casing drilling technology and alsocompletes the entire structural design and interface design.Stakes of132mm: the axial drilling pressure is14kN, the maximum outputtorque is5kN·m, the maximum speed is100r/min, and the power is20kW;As well as it detemines topology design and anti-blocking design, and thenchecks the static strength and rigidity;(4) According to the cutting mechanical mechanism, with HyperWorks andAbaqus, this paper establishes the cutting model of the a reaming rotary drill withpipes, and analyzes the related factors. The result shows that velocity androtaty speedhave an influence on drilling cutting force.100r/min and4mm/s can provide the best force closeest to the theoretical value.(5) For different drilling depths, six experiments are carried out for the drillingtime. The average speed is from12m/h to14m/h, and it verifies the rationality ofdynamic parameters experimentally.