复杂地质条件坝基帷幕灌浆钻孔成孔质量控制

Quality Control of Drilling Hole for Curtain Grouting of Dam Foundation under Complex Geological Conditions

JC水电站大坝坝基地层复杂,帷幕灌浆钻孔施工时,受岩石力学性能性的影响,钻孔方向会发生偏差,从而会影响帷幕灌浆的质量。笔者通过地质条件及岩性、施工工艺、钻孔设备选择等分析影响钻孔成孔质量的主要原因,采取调整钻压、钻速及钻孔回次进尺等多种措施。对于复杂地层的钻孔施工,在灌浆钻孔施工前,应充分了解掌握地质资料及岩石地层的岩性、各向异性以及完整程度等特征,提高钻机操作人员的技能水平和现场管理水平等,合理选择钻机、钻具和钻进方法。同时,需根据钻进过程中的孔内地质变化情况适时调整钻机压力和速度以及冲洗液的类型和流量等,从而保证钻孔的成孔效率和质量,为确保灌浆质量打下基础。

The dam foundation layer of JC Hydropower Station is complex.Due to the influence of rock mechanical properties,the drilling direction will deviate during curtain grouting drilling,which will affect the quality of curtain grouting.Based on the geological conditions,lithology,construction technology and drilling equipment selection,the paper analyzes the main reasons affecting the quality of drilling,and takes various measures such as adjusting bit pressure,drilling speed and drilling return footage.For drilling construction in complex strata,before grouting drilling construction,it is necessary to fully understand and master geological data and lithology,anisotropy and integrity of rock stratum,improve the skill level and on-site management level of drilling rig operators,and reasonably select drilling rig,drilling tools and drilling methods.At the same time,it is necessary to adjust the pressure and speed of drilling rig and the type and flow of flushing fluid according to the geological changes during the drilling process,so as to ensure the drilling efficiency and quality,and lay a foundation for ensuring the grouting quality.