Abstract
Many damages of historical tumulus mounds are caused by precipitation associated with slope failure of tumulus mounds and deterioration of the stone chambers. Rainwater infiltration control is hence indispensable for conservation of tumuli. A capillary barrier is one of feasible options. A barrier is formed at the contact between a finer soil layer and an underlying coarser one. The infiltrating rainwater in the upper layer is diverted at the contact without flowing down to the underlying layer. In this paper, the mechanism of a capillary barrier and the factors that affect on the diversion capacity are studied by model chamber tests. Then, a series of numerical analysis is conducted to simulate the chamber tests. The calculated performance reveals that a barrier functions with the difference in hydraulic conductivity in the two layers. Degree of the diversion is controlled by the intensity of precipitation, the inclination of contact plane and the thickness of the upper layer because the hydraulic conductivity of the soil layers in the steady state changes to keep the total volume of seepage water when the three factors change.
