砾石土心墙料水力劈裂试验研究

Experimental study on hydraulic fracture of gravelly soil core

在改进的三轴仪上开展了两种不同级配砾石土心墙料的水力劈裂试验。根据试验结果得到了以下结论：砾石土心墙料的自身性质与围压是影响劈裂压力的关键性因素,水力劈裂破坏主要表现为击穿破坏;相同试验条件下,随围压、固结比和水压加荷速率的提高,水力劈裂试验的流量降低;对于砾石土心墙料,当粉粒与黏粒含量较高时,由于颗粒间的胶结力更强,相同围压、固结比和加载速率条件下试样的破坏劈裂应力要更高,但不同级配砾石土的劈裂压力随围压的增长幅度变化不大;固结比或轴向应力对砾石土心墙料的劈裂压力影响不大,在文中试验条件下,加荷速率对破坏劈裂压力影响也不大。

The hydraulic fracture tests on two kinds of graded gravelly soils are carried out by using the improved triaxial apparatus. For the hydraulic fracture pressures on the gravelly soils, the soil properties and confining pressure are the key influence factors. The hydraulic failure mode of gravelly soils is always shown as breakdown. The flow capacity in the tests decreases with the increase of the confining pressure, consolidation ratio and injection pressure rate. The hydraulic fracture pressure increases with the fine particle content of the gravelly soils because of the self-cohesiveness. However, the effect on the fracture pressure with the increasing confining pressure is similar for different graded gravelly soils. The consolidation ratio or axial stress has the slight effect on the fracture pressures, and so does the hydraulic pressure rate.