Application Study On Fracture Failure Criterion And Parameter Measurement Of Frozen Soil

As soil source, basement of buildings in cold regions and low temperature environment of structures, frozen soil plays an important role for building safety and utility. Research on characteristics of failure for frozen soil is one major component of frozen soil mechanics. To investigate the characteristics, in this study the fracture failure criteria are found which are applicable to frozen soil. Fracture toughness testing has been done to undisturbed frozen soil and remolded soil in Liaoning region, and field testing results can be calculated by the ones of remolded soils' fracture toughness testing in lab. The results have been carefully compared, and the relations between them have been presented. Moreover, compression fracture toughness testing and compression and shear fracture toughness testing have been done in wing cracks which are never used in frozen soil testing. Finally, the studied theory is applied to irrigation engineering.In the first and second parts of this paper, theory of fracture mechanics of the frozen soil has been presented. A general strength theory based on fracture mechanics was proposed, and the validity of the theory of fracture failure criteria using in frozen soil was discussed.In the third part, a new testing of fracture toughness has been done to typical frozen soil in Dalian and Shenyang of Liaoning Province. The fracture toughness values for different kinds of cracks extension are determined, such as the plane strain fracture toughness for mode I cracking (K_IC), fracture toughness for mode II cracking and the mixed mode I-II of frozensoil. Under the same conditions, the fracture toughness values of remolded soil are measured. By comparing these two group results, the relations between them have been given out.In the fourth part, compression fracture toughness testing and compression and shear fracture toughness testing have been done in wing cracks. The results are compared and analyzed by using two different methods, then the rules about them are set up.In the fifth part, all theories and conclusions apply to irrigation engineering to resolve practical problems. It is proved that the fracture failure criteria is more applicable to frozen soil.The last part is discussions and prospects on the frozen soil study by using fracture mechanics theories and continuum damage mechanics.Acknowledgement: this study is supported by the Chinese NSFC, the project number is 50278010 and 10472020, we highly appreciate the support.