基于仪器钻进系统的风化花岗岩地层界面识别

针对香港风化花岗岩场址勘探,在液压旋转钻机上安装钻孔过程监测系统(drilling process monitoring,DPM),对有效轴压力、钻具转速、冲洗压力、钻头位移及穿孔速率进行了实时监测.采用变斜率作为显著性指数,对地层中的主、次界面进行了识别.t检验表明,DPM系统对岩土界面识别的置信度为99%.此外,对穿孔参数在界面处的变化分析表明,这些参数随孔深的变化曲线在界面处存在不同涨落,轴压力和穿孔速率对界面上岩石强度变化的响应度为81.82%.

Interface identification in weathered granite strata based on a instrumented drilling system

A hydraulic rotary drill instrumented with a drilling process monitoring system (DPM) was used for site investigation in Hong Kong weathered granite foundation engineering. The penetrating parameters such as effective thrust force, rotational speed, flushing pressure, penetrating rate and displacement of the bit were monitored in real time. A varied slope was defined as a significant index for identification of dominative and subsidiary interfaces in the granite site. The result from t-test shows that the confidence of the DPM in identification of the geotechnical interfaces is 99%. Besides, the analysis of variation of the penetrating parameters at the interfaces indicates that there are different fluctuations at the interfaces in the curves of the parameters with borehole depth. The response degree of effective thrust force and penetrating rate to the variation of rock strength at the interfaces is 81.82% alone.