In large-scale water diversion projects, especially in the central and western regions of China, long-distance deep buried tunnels are generally involved. Therefore, it is essential to carry out field tests to obtain the permeability of the rock mass through which tunnels pass. However, the test holes of large-scale water diversion projects are basically located in mountain areas with complex hydrogeological conditions. Meanwhile, the test holes are far apart and large in depth. As a result, traditional pumping tests cannot meet the requirements. Therefore, the slug test was chosen as the main test method, and the calculation results of the water injection test, the water pressure test and the slug test are analyzed and compared. The calculation results of the three test methods are basically consistent. However, the water injection test and the water pressure test are difficult to implement at a large scale due to many environmental constraints, complex test equipment, long test periods and other factors. Furthermore, the Kipp model, the CBP model and the proposed HWS model, considering the effect of the finite thickness well-skin layer for the first time, were used to analyze and process the slug test data, respectively. The curve fitting effect of the Kipp model was the best, but the calculations were generally larger. The difference between the CBP model and the proposed HWS model is smaller in the calculation results; however, the curve fitting effect of the CBP model is the worst, and the CBP model needs to be further improved. The curve fitting effect of the proposed HWS model was between that of the Kipp model and the CBP model, and the proposed HWS model can be applied to the parameter calculations of the slug test with well-skin. In general, with reference to the criteria for the damping coefficient of the aquifer in the Kipp model, the Kipp model was applicable to the slug test for test holes without well-skin and an aquifer damping coefficient between 0.1 and 5.0. The CBP model was applicable to the slug test under the conditions of no well-skin and an aquifer damping coefficient greater than 2.0. The novel proposed HWS model was applicable to the slug test when the aquifer damping coefficient was greater than 1.0 under the conditions of no well-skin, positive well-skin and negative well-skin.

Based on the proposed calculation method for determining the different dip angle fracture permeability coefficients derived from the well flow vibration equation and the self-developed slug test system, research on the slug test in a field in fractured rock mass was carried out based on the underground water sealed cavern project of the National Huangdao Petroleum Reserve. The formation lithology of the test site was granite gneiss, and the fractures were not developed, which is conducive to the research of slug tests on fracture permeability. On the basis of obtaining the geological information of boreholes by using the self-developed slug test system, comparative research on the segmented slug test and conventional water pressure test was carried out. The test results show that the proposed slug test method and self-developed test system has good accuracy and applicability for determining the fracture permeability coefficient, equivalent permeability coefficient and rock mass permeability coefficient tensor, which is more convenient and efficient than other test methods.

In the process of slug test in the field, mud and debris may infiltrate into the aquifer during the formation of the test well, and a poorly permeable annulus area appears around the test well wall. This is called the positive well-skin effect, which can have a significant impact on the results of slug tests due to the characteristics of a slug test. Therefore, to carry out the research on the determination of aquifer permeability coefficients by slug test under the influence of positive well-skin effect, a mathematical model of a slug test considering the positive well-skin effect was constructed. The Laplace transform method and the AWG algorithm were used to solve for a series of standard curves, and specific steps were given for calculating aquifer permeability coefficients by slug test under the influence of positive well-skin effect. Meanwhile, an indoor test model with positive well-skin effect was constructed, then several sets of slug tests and pumping tests with different excitation strengths were carried out. Based on this study, the presence of positive well-skin layer had a great impact on the aquifer permeability coefficient determined from both the pumping test and Kipp model of slug test, resulting in smaller results. The HWS model overcomes the influence of positive well-skin effect. This will further improve the theory of slug test, increase the accuracy of slug test in determining the permeability coefficient, and promote the application scope of slug test. It is therefore possible to discern the well-skin factor and determine the aquifer permeability coefficient by fitting the slug test data to a standard curve.

Based on the hidden karst exposed in Jurong Pumped Storage Power Station, combined with the field exploration data, the temporal and spatial development characteristics of hidden karst in the power station area are analyzed using the methods of specific solubility and specific corrosion, water chemical composition analysis, borehole television imaging, tracer test, and water pressure test. The results show that the karst development in the study area can be divided into three periods: pre-Cretaceous, Pleistocene, and modern karst. Karst development is controlled by soluble rock, non-soluble rock, and their combination, and the development direction is basically consistent with the fault strike. Karst caves are mainly distributed below the elevation of 100 m, with different shapes and scales and randomness. Non-soluble rocks and impure carbonate rocks are widely distributed in the study area, and surface karst is not developed. The underground karst caves are filled with red clay, and the rate of groundwater circulation is slow. The existence of geological bodies such as rock veins causes the groundwater levels to have obvious double-layer characteristics, which results in weak connectivity between karst caves. Although the karst in the power station area has a certain hydraulic connection with the surface water outside the area, the hydraulic connection of karst in the power station area is generally weak. The research results provide a scientific basis for the anti-seepage measures of underground powerhouses.

As important parameters for characterizing heat transfer, thermal property parameters of aquifers and rock-soil skeletons have important research significance in the development and utilization of geothermal resources. The slug heat test is inspired by the slug test, and the heat is instantaneously excited in the test well so as to change the temperature of test section in the test well instantaneously. Based on the thermal radial convection-dispersion theory and the principle of heat conservation, the theoretical model of the slug heat test is established, and the model is solved by Laplace transform and inverse transform to obtain multiple sets of standard curves under different conditions. The slug heat tests were conducted in the indoor model, the slug heat test data under different hydrodynamic conditions were fitted with the standard curves and the thermal property parameters, including effective thermal conductivity, stagnant thermal conductivity, thermal mechanical dispersion coefficient, thermal dispersive degree, thermal diffusivity, heat capacity of aquifer, heat capacity and thermal conductivity of rock-soil skeletons, were accurately obtained. The test results are in good agreement with the empirical values. Meanwhile, the effective thermal conductivity of the aquifer also clearly increases with the increase of flow rate. The excitation temperature difference had little effect on the effective thermal conductivity of the aquifer. At the same time, numerical simulation methods are used to establish a numerical model consistent with the indoor test model, and the numerical model is assigned with the thermal property parameters obtained from the indoor slug heat test, and the measured values of temperature changes in the test well during the slug heat test under different hydrodynamic and excitation strength conditions are compared with the simulated values for verification. The research results show that the slug heat test has the characteristics of high applicability, simple operation and rapid testing, and can effectively determine the thermal properties parameters of aquifers and rock-soil skeletons.

The parameter variations in the aquitard have an important influence on the migration laws of contaminants in the aquitard. In order to study the influence of dynamic changes in parameters during pumping on the migration laws of Light Non-aqueous Phase Liquid (LNAPL) in the aquitard, the one-dimensional consolidation and groundwater flow equations for the aquitard were employed to derive the governing equations for the migration of LNAPL in the aquitard. A self-designed experimental platform was developed to investigate the effects of the pore water pressure, consolidation deformation, and pumping rate on LNAPL migration during pumping. The laboratory experimental results indicated that during pumping, the migration behavior of LNAPL in the aquitard typically exhibited a trend toward the pumping well and the overlying aquifer. The closer to the pumping well, the greater the change in the pore water pressure, the greater the amount of consolidation deformation, the earlier the state of densification, and the slower the migration rate of LNAPL in the aquitard. The nearer to the bottom of the aquitard, the larger the amount of consolidation deformation in the aquitard and the slower the migration rate of LNAPL in the aquitard. Also, the pumping rate had an important influence on groundwater flow movement and contaminant migration. The characteristics of parameter variations in the aquitard and laws of LNAPL migration during pumping were systematically studied and analyzed; these research results can provide a reference for the prediction and remediation of LNAPL in contaminated sites.