## 5 Conclusions  
1. The upward movement of the capillary zone roof caused by a rise in the groundwater level can increase the soil volume water content of layers below the depth of 5.0 m. The silty clay layer at the depths from 4.4 m to 5.7 m has a certain retardation effect on the cohesive soil water infiltration, which reduced the soil moisture content's change in the cohesive soil layer above the depth of 5.0 m caused by groundwater level changes. The soil profile of the field test site could be mainly divided into zones: the sensitive zone of rainfall infiltration (0-1.4 m), the buffer zone of rainfall infiltration (1.4-3.5 m), the migration zone of rainfall infiltration (3.5-5.0 m), and the rainfall infiltration and groundwater level co-influenced zone (5.0-15.0 m). The effects of micro-confined groundwater level dynamic changes were taken into consideration when dividing into zones. 2. We divided the dynamic change in soil volume water content into a \"dehydration period\" and a \"water absorption period\". Soil layers above the depth of 4.5 m continued infiltrating to lose water from the surface to the bottom in the unsaturated zone during the dehydration period without rainfall. The moisture decrease in the soil layers below 4.5 m started in advance in the 1.4-4.5 m range in the \"dehydration period\", affected by a groundwater pressure decrease. The soil moisture begins to infiltrate and migrate downward after reaching a positive water potential gradient, and then soil water continues moving downward through the whole profile gradually, layer by layer. The soil moisture response time of different layers shows a lag from the surface to the bottom in thick cohesive soil. Soil water in the unsaturated zone can infiltrate gradually into the saturated zone and finally recharge the groundwater under multiple rainfalls' accumulations. 3. The thick cohesive soil profile in the field test site can be divided into three zones. The first zone, named the shallow mixed zone, was affected by precipitation and evaporation. The depth of its bottom was affected by evaporation, but it was never deeper than 200 cm in any period. The second zone, which had no evaporation, named the steady zone, ranged from the bottom of the shallow mixing zone to the top of the capillary saturation zone. Soil water content was only affected by precipitation infiltration, which caused stable effective recharge to the soil layers below by meansof piston flow. The third zone, with only piston flow, named the deep mixing zone, ranged from the top of the capillary saturation zone to 1500 cm and was introduced to form the new conceptual model of the vertical movement of cohesive soil water when taking micro-confined groundwater level dynamic changes into consideration. Soil water above this zone and groundwater recharged together to the deep mixing zone when the groundwater level increased due to rainfall, and the soil water of this zone recharged to the groundwater. This research introduced a new mode as a reference for groundwater recharge studies. 4. The cumulative water flux at the depth of 200 cm was the effective infiltration recharge from precipitation to soil water in the vadose zone, which can be totally absorbed in cohesive soil and can finally recharge to groundwater. The precipitation infiltration recharge coefficient we obtained through simulation is 0.1389. The cumulative water flux of the cohesive soil layer at the depth of 1100 cm (349 mm) could be considered as the actual recharge from the cohesive soil layer to micro-confined groundwater, which is greater than that of the depth of 200 cm (234 mm). The difference was not only because of a significant lag effect caused by a low saturated permeability coefficient and the long recharge path of the cohesive soil, but also by the exchange capacity, controlled by micro-confined groundwater pressure to a great extent. The exchange capacity decreased as the micro-confined groundwater pressure head increased, leading to a decrease in the rate of the actual recharge of groundwater.