饱和砂土中浅埋单药包爆炸液化特性分析

堰塞坝和挡水堤坝的爆破泄洪均可能涉及饱和土中的浅埋爆炸问题,然而关于饱和土中浅埋炸药爆炸引起的动态孔隙水压力及液化的研究则鲜有报道。基于饱和砂土中的浅埋单药包爆炸液化现场试验,分析了浅埋爆炸引起的土中超孔隙水压力变化特征,研究了药量、埋深和爆距等因素对土中超孔隙水压力上升的影响。在评价饱和砂土中封闭爆炸液化经验预测方法的基础上,提出了考虑药包埋深和比例距离的修正的液化预测经验模型,并与金银岛爆炸液化试验数据进行对比验证。研究结果表明,修正后的液化预测经验模型可以描述比例埋深对爆后孔隙水压力上升的影响,可以较为精确地评价和预测浅埋单药包爆炸引起的饱和土中液化的发生程度及范围。研究成果可以作为饱和土中封闭爆炸液化经验预测方法的补充和完善。

Characteristics of liquefaction induced by single shallow-buried detonation in saturated sand

The practical problems of blasting landslide dams or water retaining dams may involve a subject of shallow-buried explosions in saturated soils. However, the studies on dynamic pore water pressure and liquefaction induced by a single shallow-buried detonation are rarely found in open technical literatures. A series of single shallow-buried detonation field tests in saturated sand are conducted to study the characteristics of the excess pore water pressure and the influences of charge mass, buried depth and distance on the generation of pore water pressure. Then the empirical prediction methods based on fully-contained detonations are evaluated. And a modified empirical model with respect to scaled distance and scaled buried depth is proposed to predict the excess pore water pressure or liquefaction based upon the evaluations. A group of experimental data from Treasure Island liquefaction tests are used to validate the modified empirical model. The results show that the modified empirical model can describe the buried depth on the generation of pore water pressure. Meanwhile, it can be utilized to accurately evaluate and predict the liquefaction degree or range. The results can be used as a supplement and improvement to the empirical methods for predicting the liquefaction produced by fully-contained detonations in saturated soils.