同步爆扩法处理高速公路液化土地基现场试验研究

为了获得同步爆扩法处理高速公路液化土地基的实施方法和参数，验证理论及模型试验研究成果，采用现场试验和对比分析相结合的研究方法对其进行研究．提出了合理爆扩参数、爆扩孔装填结构、爆扩方式、安全控制等同步爆扩法处理高速公路液化土地基的关键技术和实施方法．结果表明：爆扩孔的装填结构和填塞长度是爆扩成腔和同步完成爆扩腔碎石充填的关键；超孔隙水压力与爆扩距离均呈负指数规律分布，其有效范围为4～6m，排水沉降主要发生在爆扩后2～3d内，地面沉降量达0．3～0．4m；爆扩地面震动频率为5～15Hz低频大振幅震动，爆扩安全距离为40～50m．采用该技术处理后的地基土体物理力学特性提高，液化消失．

Field Test Study on Treatment of Liquefied Soil Foundation of Expressway with Synchronous Blast-Enlargement

The constructing method and the parameters of the liquefied soil foundation of freeway treated with the synchronous blast-enlargement were obtained by field tests and relative analysis to verify the theory and model test. The key technology and optimum constructing method treating the liquefied soil foundation such as reasonable parameters, charging structure, blast-enlargement mode, and safety control were proposed. The results show that the charging structure and filling length of blast-enlargement bore were critical to forme cavity and synchronous aggregate filling. The excess pore pressure and blast-enlargement distance are negative exponential distribution, the efficient ranges of both are 4-6 m, the drainage subsidence occurred in 2 to 3 d after blasting, and the subsidence of ground was 0.3-0.4 m. The shake frequency on ground was 5-15 Hz and the safe distance was 40-50 m. The physical mechanics characteristics of foundation soil are improved and the liquefaction of soil disappear after treated by this technology.