黑岱沟矿区场地地脉动测试和分析

Microtremor Test in Heidaigou Mining Area and Its Analysis

黑岱沟露天煤矿在开采过程中由于采用大剂量的抛掷爆破从而产生了强烈的地表振动,该矿区上覆数十米黄土,研究该区域黄土覆盖场地的放大效应和卓越频率对煤矿开采爆破设计有重要意义。在现场调查的基础上,选取黑岱沟露天煤矿一号矿区的基岩面和黄土场地开展了地脉动测试,并获取了基岩和黄土场地地表的加速度时程。对测试数据采用快速傅里叶变换和单点谱比进行分析。结果表明,该矿区黄土场地的放大系数在2.7倍左右,卓越频率在2.3Hz左右。同时根据场地的实测资料建立了FLAC一维土柱模型,将基岩加速度时程作为输入计算黄土覆盖场地的微振反应,计算得到的结果与脉动测试的结果基本一致。

During the mining process of the Heidaigou open-pit coal mine,strong surface vibration was generated due to the use of large doses of thrown blasting.Since the mining area is covered with tens of meters of loess,studying the amplification effect and predominant frequency of the loess covered site in this area has important theoretical and practical significance for coal mining design.Firstly,based on the field survey,we selected the bedrock surface and loess site of No.1 mining area of Heidaigou Open-pit Coal Mine to carry out microtremor tests,and obtained the acceleration time history of the bedrock and loess site.The test data was analyzed by Fast Fourier Transform and Single Point Spectral Ratio.The results show that the magnification factor of the loess site in this area is about 2.7 times,and the predominant frequency is about 2.3Hz.Secondly,a FLAC one-dimensional soil column model is established based on the actual measured data of the site,and the acceleration time history of the bedrock is used as the input to calculate the micro-vibration response of the loess site.