Elapse Time Factor on Induced Vegetative Moisture Uptake in an Unsaturated Soil

Problem statement: Soil consolidation is generally time dependent, therefore soil displacement as a result root water uptake is space and time dependent. The time-dependent nature of abstraction of ground water by vegetation need to be evaluated in order understand the effect of time elapse on matric suction a generation and subsequent ground displacement. Approach: The current approach used the theory of unsaturated soils with modification due to assumption made in the course of model formulation with two stress state variables principles. A volume change was modeled as a result of matric suction change caused by vegetative induced moisture migration. The effect of elapsed time for full cycle are simulated for periods that covers a spring/summer soil-drying phase of 6 months followed by an autumn/winter 6 month recharge phase. Results: The results of this evaluation showed that the soil matric suction and deformation increases with time spring/summer soil-drying phase of 6 months followed decreases during autumn/winter 6 month recharge phase. There is also decreased in the suction generation and ground displacement as the lateral distance from the Lime tree trunk increases. Conclusion: This study provided a valuable and a relatively accurate means to estimate the influences of vegetation on ground taking the various elapsed times into account. The effect of rainfall has been incorporated into the simulation study, as study of this kind is not complete with inclusion of rainfall data.