Experimental on resistance to tensile stress and complete stress-strain curves of root system of Pinus tabuleeformis

The mechanisms of soil-reinforcement by roots system have been researched through the tests for the pull-resistance of roots system of Pinus tabuleeformis in the Loess Plateau.The theory analysis and compare(results) of complete stress-strain curve show that load,stress,extend and strain increase pro rata, complete stress-strain curves present straight line relation in root system initial stage after tension.As the continuation of pulling force increases after loading over elastic limit,plasticity out of shape takes place in the root system,the complete stress-strain curves deviate from the straight line gradually, reflect the highly non-linear elastic characteristic.The test indicates that the root system tensile strength of the Pinus tabuleeformis have extremely close dependence to resist the amount of tension elastic model,according to results of the test,the unify mathematic expression of resistance to tensile stress and complete stress-strain curve is put forward,Which merge better between theory curves and experimental curves.