土石坝沥青混凝土心墙水力劈裂研究

Study on hydraulic fracturing of asphalt concrete core in earth-rock dam

结合Finstertal坝的运行资料和室内三轴试验结果,分析了沥青混凝土心墙在蓄水运行过程中存在产生水力劈裂的前提条件,主要包括:沥青混凝土的剪胀性以及渗透系数对孔隙率、骨料级配的依赖性;对沥青混凝土进行了室内水力劈裂试验,并对试验资料进行数值计算的结果表明,试件在受拉时形成的局部微小裂缝的诱导下发生了水力劈裂;结论对高沥青混凝土心墙堆石坝建设具有一定的指导意义。

Using the operation data of the Finstertal dam and indoor triaxial test results, this paper demonstrates the conditions required to hydraulically fracture an asphalt concrete core under normal reservoir storage, such as dilatancy of asphalt concrete at low confining pressure, and dependence of hydraulic conductivity on porosity. A hydraulic fracturing test of asphalt concrete was carried out and its conditions were simulated numerically. The results reveal that the tiny tensile cracks of test specimens are the inducing factors of hydraulic fracturing. This is significant to the construction of high rock-fill dam with an asphalt concrete eore.