基于AMD和爆破荷载耦合作用下的深凹露天矿边坡失稳研究

AMD是化工(金属)矿边坡体破坏的一种特殊方式,与爆炸应力波共同对边坡体产生作用.新桥深凹露天矿边坡岩体的原位剪切试验、点载荷试验、室内模拟AMD作用试验表明:AMD蚀化后的石英砂岩,岩体层面间的抗剪强度和粘聚力减小的幅值约为13.2%～21.3%;层面间内摩擦角减小幅值在5.0%～7.5%之间;AMD一般影响垂直边坡体内部在60～100 m范围内的岩体力学性质.数值分析表明:(1)AMD对边坡体的作用主要集中在弱化区域内,边坡体的底脚和AMD作用中心区域的剪切应力减少了52.0%和64.7%;(2)随着边坡体高度和距离的增加,远场爆炸应力波对边坡扰动幅值的增加趋势明显,边坡顶部和断层部位的响应突出,损伤效应明显;边坡底脚扰动幅值最小,临空面附近台阶的扰动幅值明显大于边坡体内部;(3)AMD与爆破荷载耦合作用后,边坡体内部的应力分布主要呈现出爆炸应力场的特征,AMD影响区域形成了一个剪切应力弱区.台阶顶部最大剪切应力比单一爆炸应力场增加了1.63倍,形成了一个不稳定的弱区.图12,表3,参14.

Study on Instability of Concave Slope in Open Pit by AMD and Explosive Loading

AMD is a special breakdown method of slope in chemical (metal) mine, having absolutely impact on slope together with stress wave from explosion. Home position shear tests of slope rock, point loading tests and indoor AMD simulation action tests in XingQiao concave slope had show shearing strength and coherence between body layers of quartz sandstone decrease by 13.2%~21.3% after attacked by AMD, the angle of internal friction between layers is decreased by 5.0%~7.5%, in general, AMD affects the rocks mechanical property at range of 60~100 m interior the perpendicular slop. Data analysis shows: 1) The actions to slope are major focused on zone of weakness, shearing strength of slope foot and AMD centre are reduced by 52% and 64.7% separately. 2) The explosion stress wave of long distance field has obviously increasing influence to disturbance amplitude value of slope with increasing of the slope height and distance, the response of the top of slope and fault region are obvious as well as damage effect; the foot of slope is with smallest disturbance amplitude value, the disturbance amplitude value of the step close to free face is obviously bigger than the interior of slope. 3) With the coupling effect of the AMD and explosion loading, the stress distribution inside of slope mainly presents characters of explosion stress field; the area affected by AMD becomes a weak area of shearing stress. The maximum shearing stress on the top of step increased by 1.63 times comparing with single explosion stress field, an unstable weak area is formed.12figs.,3tebs.,14refs.