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目前,通常采用原型监测的方法了解土石坝运行期渗流情况,但对稳定期渗流研究较多,而未有在土石坝初次蓄水期原位钻孔渗流试验相关研究。瀑布沟水电站大坝由于788.00 m高程以上心墙较薄且早期未布置监测仪器,前期监测显示大坝可能存在抗渗薄弱区域,在初次蓄水期于心墙0+131及0+434断面进行了原位钻孔渗流试验。通过对试验成果分析并与监测成果相比较,得出大坝心墙0+131、0+434断面部分高程存在渗透薄弱带。试验结果表明,通过精心组织设计施工,进行蓄水期心墙原位钻孔渗流试验是可行且有意义的。建议对反滤层保护下的裂缝土体抗渗强度进行评价,加强心墙防渗安全监测以及时掌握心墙运行状况。其试验研究可以为其他砾石土心墙坝的设计、施工、运行期的安全提供参考。
At present, the prototype monitoring method is usually used to understand the seepage situation of earth-rock dam in operation period, but there are many researches on the seepage of the earth-rock dam in the steady state, but there is no relevant research on the in-situ drilling seepage test in the initial storage period of the earth-rock dam. As the dam wall at Pubugou Hydropower Station is thin at 788.00 m above sea level and monitoring instruments are not provided at the early stage, preliminary monitoring shows that the dam may have weak seepage-resistant areas. During the initial storage period, the core walls are at 0 + 131 and 0 + 434 sections In situ drilling seepage test. Through the analysis of the test results and comparison with the monitoring results, we can draw the conclusion that some of the elevations in the section 0 + 131, 0 + 434 of the dam core wall have weak permeability zones. The test results show that it is feasible and meaningful to conduct in-situ drilling percolation test by carefully designing and constructing the core wall. It is suggested to evaluate the anti-seepage strength of cracked soil under the protection of anti-filtration layer, to strengthen the anti-seepage monitoring of the core wall and to grasp the operation status of the core wall in time. The experimental study can provide reference for the design, construction and operation of other gravel soil core wall dams.