ABSTRACT
The study aims to clarify the dynamic change characteristics of seepage and deformation and stress behavior of a cross-section of Karez in Turpan. Based on unsaturated soil and saturated soil mechanics, a physical model is established for the water collecting section of Karez. The coupling analysis of the seepage field and stress field is carried out for the water collecting section of Karez by using finite element software ABAQUS. The results show that the height of saturation between 0.995 and 0.526 during drought in the catchment area is 0.93 cm, and the height of saturation between 0.980 and 0.521 during sufficient water in the catchment area is 105 cm. The height of saturation between 0.974 and 0.526 during the flood in the catchment area is 115 cm. The main permeation direction is the bottom of the Karez well in the dry season. The displacement and strain caused by the wall circumference of the underground channel are simulated and calculated when the water level is 3.6 m when there is sufficient water. A maximum expansion of 6.6 cm occurs at the wall. In the vertical direction (Y direction) and with stress release during excavation, displacement up to 8 cm occurs at the bottom and down to 11 cm at the top. Seasonal water level variation of the underground channel in the catchment area has little effect on the water level variation of the underground channel but has a great influence on the seepage of water on the wall of the Karez and little effect on the soil deformation between the underground channels. The top surface of the underground channel catchment is the place with the largest displacement deformation, and the bottom of the underground channel catchment is the place with the greatest stress. Groundwater seeps underground in the direction of soil relaxation, thus increasing the risk of wall erosion of Karez. Therefore, the stability of soil on the wall of the underground channel should be considered. The project team systematically studied the destruction mechanism of the water catchment of Karez by means of simulation calculation. The research results provide a certain theoretical basis for the repair of Karez, thus reducing the economic burden of farmers in the repair of Karez.
