Experimental Research And Theoretical Analysis Of Frozen Soil Cutting

The commonly used methods of excavation of frozen soils are composed of blasting,hot-melting and mechanical cracking,in which the mechanical cracking is the most widely used method.The main mechanical equipment for cracking frozen soils include: soil loosening machines,road rollers,bulldozers,bucket-type excavators and chain-type excavators,etc.,which can be selected in applications according to different conditions of frozen soils.However,it is found that there always exists deficiencies in each of the above methods of excavation.Therefore,the researchers involved have carried out a study on the excavation of frozen soils by cutting,and found that cutting possesses the advantages of less energy consumption and high efficiency in comparison to other methods.Based on mechanics of frozen soil and mechanics of materials,the aim of this paper is arranged to optimize the design of cutting tools of frozen soils.By using an equipment consisted of rotary cutting machine and straight-edged cutting tool with sharp-angle,a series of cutting tests on cylindrical specimens of frozen soils made by Lanzhou loess have been performed in the low-temperature laboratories.Meanwhile,involved with the strength criterion of Mohr-Coulomb and the theory of limit equilibrium,a cutting model has been established,and the validity of which has been confirmed by compared with the experiment data sets.In sum,the main conclusions of this paper are depicted as follows:1.The growth of depth of cutting results in the approximately linear increase in the cutting force;2.With the moisture content increasing,the cutting force first increases.When the moisture content is about 17%-18%,the cutting force reaches its maximum.Afterwards,the cutting force remains almost unchanged or decreases slightly as the moisture content increases continuously;3.In the executed cutting speed range(80.86mm/s,116.43mm/s,161.71mm/s),the cutting force does not change significantly with the cutting speed;4.The cutting mass increases with the increases of cutting depth and moisture content;5.By means of the established cutting model,the theoretical formula of cutting resistance is obtained,and then is adopted in the regression analysis to fit the experiment data sets.