| The study on the influence of fracture mode on the water\|carrying capacity of stalk composite pipe (SCP) is of great significance for the promotion of the mechanized SCP irrigation. With the SCP being the experimental material, the free discharge experiment was carried out in the laboratory from November 2020 to April 2021 to preliminary investigate whether the water would flow through the fracture; The treatments were as follows: the complete SCP (D0) , the inclined cut (45°) fracture with 1 cm spacing (D1) and the straight cut fracture with 1 cm spacing (D2) . A orthogonal experiment with three factors at three levels was designed with fracture modes including inclined cut (45°), straight cut and free cut (broken) , working pressure including water head of 30, 50 cm and 70 cm and water supply including 30, 40 and 50 L. Meanwhile, with the buried complete SCP as the control group, a field experiment was conducted to test the performance of the buried SCP to investigate the influence of fracture mode of the SCP on its hydraulic performance. The results were as follows: Under the condition of free discharge, the head pressure of D1 and D2 treatment decreased by 11.6 and 14.4 cm respectively compared with that of D0 treatment (47.9 cm) . The two treatments were ranked as: D2＜D1, meaning that the influence of straight cut was bigger than that of inclined cut (45°) . Under the condition of buried discharge, pressure distribution in SCP with different fracture modes were ranked as: straight cut < inclined cut (45°) < free cut (broken); water seepage rates were ranked as: inclined cut (45°) ＞straight cut＞ free cut (broken) . Compared with straight cut and inclined cut (45°) , the free cut (broken)had less influence on the flow running through the fracture. When SCP was buried under the ground, the pressure in the pipe was distributed as an inverted U with the increase of working pressure. It showed that with the working pressure increasing to a certain extent (more than 50 cm in the experiment) , the water flow at the fracture increased, or even produced a piping, the pressure in the pipe decreases instead of increasing, and the continuity of flow gets worse before and after the fracture. To sum up, the fracture spacing of the SCP should be controlled within 1 cm, and the working pressure should be 50 cm water head, which had little influence on the hydraulic performance of the SCP and guaranteed its irrigation performance. |