Study on Hydraulic Fracturing of Clay Anti-seepage Body in the Upstream of Earthrock Dam Under the Condition of Drought Flood Abrupt Alternation
The condition of drought-flood abrupt alternation,as an extremely rare event,frequently occurs,which can easily lead to the expansion of defects in the anti-seepage body and trigger engineering accidents.On the basis of mod-el experiments and numerical calculation analysis,the hydraulic fracturing problem in the clay anti-seepage body of earth rock dams under the condition of drought-flood abrupt alternation was explored.The results indicate that the drought process reduces the permeability of soil matrix and leads to the formation of cracks in the anti-seepage body,providing a necessary condition for hydraulic fracturing to occur.Theoretical analysis has derived the theoretical value of seepage pressure for hydraulic fracturing failure along the plane where the crack is located.In the centrifugal test model,it was found that the pore pressure in the covering layer decreased sharply while the pore pressure in the sand layer increased sharply,indicating that the crack was subjected to high water pressure and split through the anti-seepage body.The measured pore water pressure value at the crack is basically consistent with the theoretical derivation results.The com-pressive stress inside the soil at the crack first gradually increases,then decreases continuously and finally transforms into tensile stress,leading to hydraulic fracturing.The research results have guiding significance for the safe operation of earth rock dams under the condition of drought-flood abrupt alternation.
NETL
NSTL
万方数据
