The Effect of Cyclic Loading on Root Mechanical Properties of Caragana microphylla

In order to explore the efficiency of soil consolidation with vegetation roots under cyclic loading in arid and semi-arid ecologically vulnerable areas, the tensile properties of the 1.00≤d≤4.00 mm diameter straight roots of Caragana microphylla under 50 times cyclic loading were studied using the TY-8000 servo type machine. As the results show, the ultimate tension of the 1.00≤d≤2.00 mm, 2.00 < d≤3.00 mm and 3.00 < d≤4.00 mm straight root was respectively (134.42±14.17), (285.24±27.65) and (420.24±27.36) N under cyclic loading of 30% of the ultimate force of a single loading, which increased by 48.20%, 42.71% and 29.07% respectively compared with the single loading; the ultimate tension of the straight root was (70.53±10.3), (155.15±21.04) and (287.84±22.65) N, under cyclic loading of 70% of the ultimate force of a single loading, which decreased by 22.23%, 22.37% and 11.58%, respectively compared with the single loading. The ultimate tension and tensile strength of each diameter class under cyclic loading were significantly different from those of the single loading (P < 0.05). It is shown that moderate cyclic loading can promote the ability of the root system for soil consolidation and excessive cyclic loading will cause damage to the root system and reduce its tensile properties. The gray correlation analysis shows that the diameter, loading times and loading speed all affect the mechanical properties of the root system.