利用微动探测技术调查尾矿库坝体地基稳定性

AN INVESTIGATION ON THE STABILITY OF THE FOUNDATION OF A TAILINGS DAM BY MICROTREMOR DETECTION TECHNIQUE

某矿区尾矿库坝脚一监测点四个月以来位移量达到4cm之多,尾矿库附近曾发生过采空和塌陷,若坝体地基发生位移,则会对坝体稳定性产生重大影响。本文采用微动剖面探测技术查明研究区地质状况,对坝体地基进行稳定性评价。通过获取该监测点周边地下200m内视S波速度结构特征,证实了该监测点位于断层交汇处,周围地质条件稳定,已知东面矿山采矿巷道和塌陷未向尾矿库坝体方向延伸,位移诱因推测为浅层地表因素或其他因素。微动探测岩石视S波速度与实验室推断横波速度非常接近,探测断层位置与已知地质资料相符,与CSAMT探测结果相符,同时分辨率更高、细节更好,在研究区内成功识别出沙子堡平移断层组一处小断裂,方法优势明显。

In a mining area,the displacement of a monitoring point reached up to 4 cm within a four-month period at the foot of a tailings dam,in the vicinity of which a goaf collapse had occurred before.If a displacement happens to the foundation of the dam,the stability of the dam will be greatly undermined.In this paper,the technique of microtremor profile detection is used to disclose the geological conditions of the study area and evaluate the stability of the dam foundation.By obtaining the characteristics of apparent S-wave velocity structure within 200 m underground around the monitoring point,it is confirmed that the monitoring point is located at the intersection of faults,but the surrounding geological conditions are stable.It is known that the mining roadway and collapse in the mine to the east have not extended toward the tailings dam,so the displacement is thought to be resulted from the shallow surface or from other factors.The apparent S-wave velocity of the rocks from microtremor detection is very close to that inferred in laboratory.The locations of the detected faults are consistent with the known geological data.In conformity with the CSAMT detection results,the microtremor detection is higher in resolution and better in details.