预裂缝充水环境下减振效果研究

STUDY ON VIBRATION REDUCTION EFFECTS UNDER FILLING WATER IN PRESPLITTING CRACK ENVIRONMENT

为研究预裂缝充水对减振效果的影响,运用ANSYS/LS-DYNA建立有限元模型,对有、无预裂缝及预裂缝充水高度不同的台阶爆破进行了数值模拟,获得预裂缝后质点峰值振动速度。对比分析不同情况下的预裂缝后质点峰值振速,结果表明:预裂缝充水小于0.2倍预裂缝深度时,充水对减振效果影响小,减振率降低约3%,预裂缝后质点峰值振速衰减符合指数关系;预裂缝充满水时,充水对减振效果影响大,减振率降低约30%,预裂缝后质点峰值振速衰减符合萨道夫斯基公式。因此,工程实际中应避免预裂缝中大量充水。

In order to analyze the impact of filling water in presplitting crack on vibration reduction effect,a finite element model was established by using ANSYS/LS-DYNA and numerical simulation of bench blasting under the conditions of no presplitting crack and different depths of filling water in presplitting crack were carried out.The values of peak particle velocity were obtained.Comparing the peak particle velocity under different conditions,the research results showed that when the depth of filling water in presplitting crack was less than 0.2times of presplitting crack depth,the impact on vibration reduction effect was little,the vibration reduction ratio decreased by approximately 3%,and the attenuation curve of peak particle velocity fitted the exponential relationship.However,when the crack was filled with water,there would be significant effect on vibration-isolating effect and 30% decrease of vibration reduction ratio,and the attenuation curve fitted Sadov′s formula.Therefore,it can be concluded that filling large amounts of water in the presplitting crack should be avoided in the practice.