浅埋单药包爆炸作用下饱和钙质砂基础液化数值模拟

Numerical simulation of liquefaction in saturated calcareous sand foundation induced by single charge shallow-buried explosion

为研究浅埋单药包爆炸作用下饱和钙质砂基础的液化机理,利用LS-DYNA动力分析软件建立了饱和钙质砂基础爆炸液化动力分析的数值模型,通过与已有文献的试验结果进行对比,验证了有限元模型的有效性,并进一步分析了浅埋单药包爆炸对饱和钙质砂基础孔隙水压力的影响.结果表明:饱和钙质砂基础抗爆炸液化能力较强,在相同比例距离下,饱和钙质砂的土压力峰值小于普通陆源砂;饱和钙质砂完全液化域为2.35 m/kg^(1/3),与普通陆源松砂基本一致,孔隙水压力的影响域为4.60 m/kg^(1/3),远小于普通陆源松砂;在相同比例埋深下,爆炸当量越小,孔隙水压力达到稳定值所需时间越短,稳定孔隙水压力值越小;增大饱和钙质砂基础的密实度和采用混凝土桩加固可以有效提升基础的抗爆炸液化能力.

To study the liquefaction mechanism of saturated calcareous sand foundation under shallow buried single charge explosion action,a numerical model for dynamic analysis of saturated calcareous sand foundation explosion liquefaction was established by LS-DYNA dynamic analysis software,and the validity of the finite element model was verified by comparing with the experimental results of existing literatures.The effects of shallow buried single charge explosion on the pore water pressure in saturated calcareous sand foundation were further analyzed.The results show that the saturated calcareous sand foundation has strong resistance to explosion liquefaction,and the peak value of the soil pressure in saturated calcareous sand is smaller than that in common terrestrial sand at the same blasting distance.The full liquefaction domain of the saturated calcareous sand is 2.35 m/kg^(1/3),which is basically the same as that of the common terrigenous pine sand.The influence domain of the pore water pressure is 4.60 m/kg^(1/3),which is much smaller than that of the common terrigenous pine sand.At the same buried depth,the smaller the explosion equivalent,the shorter the time required for the pore water pressure to reach the stable value,and the smaller the stable pore water pressure value.In addition,increasing the compactness of saturated calcareous sand foundation and retrofitting with concrete piles can effectively improve the resistance of the foundation against liquefaction.