Friction Characteristics of Root-Soil Interface of Pinus Tabulaeformis and Larix Gmelinii

Using a direct drawing tests of root soil interface of Pinus tabulaeformis and Larix gmelinii, friction characteristics of the interface was examined, and the influences of loading rate and burial depth of root were analyzed. The results show that, the curves of maximum pulling force and displacement of the roots which were broken had two steps: the steep rise and steep fall, while the curves of maximum pulling force and displacement of the roots which were pulled out had three steps: the steep rise, steep fall and gentle decline. The root soil static friction and its corresponding displacement increased with increasing loading rate and burial depth respectively. Both the root soil static friction and its corresponding displacement of Larix gmelinii were larger than that of Pinus tabulaeformis.