## 3 Engineering Applications
### Central Yunnan Water Diversion Project
#### 3.1.2. Slug Test of the Central Yunnan Water Diversion Project  
As the central Yunnan water diversion project is located in a mountainous area with complex geological conditions, there are many difficulties in conducting hydrogeological tests in this area. For example, it is difficult to adopt the traditional pumping test for investigation, and the water pressure test is also limited by the site and equipment. A lot of field test work has been carried out in order to seek the theory and method applicable to the field test of the rock mass hydrogeological parameters in deep test hole. Among them, the borehole CYWD-1 is specially selected to conduct sectional comparative tests. With top-pressure plug water sealing, seven groups of sectional slug tests and variable water head water injection tests are carried out every 5-25 m according to the drilling progress and are numbered CYWD-1-1, CYWD-1-2, CYWD-1-3, CYWD-1-4, CYWD-1 CYWD-1-5, CYWD-1-6 and CYWD-1-7. Among them, the first test section is located in the borehole depth of 130-135 m; the second test section is located in the borehole depth of 135-143 m; the third test section is located in the borehole depth of 143-161 m; the fourth test section is located in the borehole depth of 161-173 m; the fifth test section is located in the borehole depth of 173-182 m; the sixth test section is located in the borehole depth of 182-196 m; and the seventh test section is located in the borehole depth of 182-196 m. The test data are respectively calculated and analyzed with the variable water head injection test and three theoretical methods of the slug test. The slug test data are fitted with the standard curves of three slug test models according to the Kipp model, CBP model and HWS model. The fitted standard curves are shown in Figure 7.  
Figure 6: The location and water delivery route of the central Yunnan water diversion project. Figure 7: _Cont._  
As shown in Figure 7, the standard curve shape of the three models is basically consistent. When the water level recovery rate gets faster, the CBP model will at first be poorly fitted. As the rate is further accelerated, especially when the aquifer damping parameter is less than 1, the HWS model will also appear to be unable to completely fit in the part of the beginning and end. Since the Kipp model has a large variation in the shape of the standard curve, it can match the measured curves at different water level recovery rates to the greatest extent, so the Kipp model has the best fit in the matching process, and the HWS model has the second best fit. The overall shape of the standard curve cluster of the CBP model is relatively gradual, and the fitting effect of the CBP model is relatively poor when the water level recovers rapidly. In general, the fitting effect of all three models can meet the requirements of the calculation. In addition, an on-site investigation of the boreholes along the Shigu water source area and the Xianglushan tunnel of the central Yunnan water diversion project is adopted. The whole hole section slug test studies are carried out in the boreholes of CYWD-2, CYWD-3, CYWD-4 and CYWD-5. Three slug test models are used for the fitting curve and parameter calculation. The fitted standard curves are shown in Figure 8.  
Figure 7: Fitting curve of the CYWD-1 slug test with a different model. (**a1**) CYWD-1-1, Kipp model; (**a2**) CYWD-1-1, CBP model; (**a3**) CYWD-1-1, HWS model; (**b1**) CYWD-1-2, Kipp model; (**b2**) CYWD-1-2, CBP model; (**b3**) CYWD-1-2, HWS model; (**c1**) CYWD-1-3, Kipp model; (**c2**) CYWD-1-3, CBP model; (**c3**) CYWD-1-3, HWS model; (**d1**) CYWD-1-4, Kipp model; (**d2**) CYWD-1-4, CBP model; (**d3**) CYWD-1-4, HWS model; (**e1**) CYWD-1-5, Kipp model; (**e2**) CYWD-1-5, CBP model; (**e3**) CYWD-1-5, HWS model; (**f1**) CYWD-1-6, Kipp model; (**f2**) CYWD-1-6, CBP model; (**f3**) CYWD-1-6, HWS model; (**g1**) CYWD-1-7, Kipp model; (**g2**) CYWD-1-7, CBP model; (**g3**) CYWD-1-7, HWS model.