石佛寺水库主坝坝基液化分析与防治

Analysis and Controlling of Earthquake Liquefaction in Shifosi Reservoir Main Dam Foundation

运用标贯法和seed简化方法对坝基的抗震液化进行了分析判别,发现坝基中粉砂和细砂层存在严重液化问题,中砂层局部存在液化问题,液化深度一般为7～9m,最大液化深度可达13.2m。依据坝坡稳定分析结果,确定上、下游坝脚内15m,坝脚外5m为坝基液化处理范围,粉砂、细砂层为主要处理地层。在实际防治工作中,采用振冲碎(砂)石桩或振动沉管砂石桩,结合水平排水对坝基的地震液化进行处理。处理后对各区砂土层的密实度及饱和砂土的地震液化进行检验,结果表明处理厚的坝基基本上达到了基础处理的目的。

To use standard penetration test and Seed＇s simplified procedure carried out analysis and differentiation of dam foundation earthquake liquefaction, have found that liquefaction issue is existed seriously in silt and fine sand layers, locally in medium sand layers, general liquefaction depth 7-9m, maximum 13.2m. Based on dam slope stability tested results, determined that upstream and downstream 15m inside and 5m outside the dam toe and foundation liquefaction processing extent, silt and fine sand are main objective layers. In practices, vibro-replacement （sand） crushed stone column or vibro-casing sinking grit column combined with horizontal drainage are used in earthquake liquefaction processing. Inspection of compactness of sand and saturated sand earthquake liquefaction have carried out after the processing, the results demonstrated that the processing has basically carried its point.