CAJ | 학술논문

水利工程中的钻孔工程具有特殊的工况，采用正循环潜孔锤钻进方法在狭窄封闭的洞室内进行钻孔施工，粉尘污染严重，施工环境恶劣，影响作业工人的身体健康。为了解决施工洞室内的粉尘污染问题，在某水电站的排水孔施工中，首次应用了潜孔锤反循环钻进技术，并在上仰孔和下行孔施工试验中获得成功，有效控制和降低了洞室内的粉尘问题，有利于维护良好的施工环境。设计的 A、B两种结构类型钻头主要差别是内喷孔的位置不同，A型钻头的内喷孔设计在花键上的各个平键之间，B型钻头的内喷孔则设计在花键的平键上。CFD数值模拟计算结果显示，A型钻头对环空抽吸的空气量是0．19998704 kg/s，略大于B型钻头的0．17752464 kg/s，说明 A型钻头的抽吸能力优于B型钻头。上仰孔和下行孔的钻进试验结果表明，内喷孔设计在花键上的各个平键之间且具有双排12个内喷孔的 A型钻头结构更为合理，在施工中 A型钻头比B型钻头的孔口粉尘少。从反循环排渣效果看，A型钻头破碎的大部分岩粉和大颗粒岩块从中心通道排出，反循环排渣效果优于B型钻头。
수리공정중적찬공공정구유특수적공황，채용정순배잠공추찬진방법재협착봉폐적동실내진행찬공시공，분진오염엄중，시공배경악렬，영향작업공인적신체건강。위료해결시공동실내적분진오염문제，재모수전참적배수공시공중，수차응용료잠공추반순배찬진기술，병재상앙공화하행공시공시험중획득성공，유효공제화강저료동실내적분진문제，유리우유호량호적시공배경。설계적 A、B량충결구류형찬두주요차별시내분공적위치불동，A형찬두적내분공설계재화건상적각개평건지간，B형찬두적내분공칙설계재화건적평건상。CFD수치모의계산결과현시，A형찬두대배공추흡적공기량시0．19998704 kg/s，략대우B형찬두적0．17752464 kg/s，설명 A형찬두적추흡능력우우B형찬두。상앙공화하행공적찬진시험결과표명，내분공설계재화건상적각개평건지간차구유쌍배12개내분공적 A형찬두결구경위합리，재시공중 A형찬두비B형찬두적공구분진소。종반순배배사효과간，A형찬두파쇄적대부분암분화대과립암괴종중심통도배출，반순배배사효과우우B형찬두。
The drilling tasks in hydraulic engineering were usually under severe conditions.In the narrow closed cavity, the normal DTH hammer drilling technique was generally applied to drill boreholes,but dust pollution will seriously affect the working environment and workers’health.To solve the dust pollution in the cavity,reverse circulation drilling technique with DTH air hammer was firstly applied to drill the drain holes in the cavity of a hydropower station, and the upward and downward holes were successfully drilled.The reverse drilling technique with DTH air hammer can control and reduce the dust pollution in the cavity.Furthermore,this technique can maintain good working environments.Two types of drill bits with different structures were designed for test,which were named as type A and B,respectively.The main difference between type A and B drill bits were the positions of suction nozzles.The suction nozzles of type A drill bit were evenly distributed between any two flat keys of the spline.While the suction nozzles of type B were distributed on every flat key of the spline.The CFD numerical simulation results had shown that the air suction rate in annular space of type A drill bit was 0.199 987 04 kg/s,which is slightly larger than that of type B drill bit with a air suction rate of 0.177 524 64 kg/s in annular space between drilling tool and borehole wall .In other words,type A drill bit can suck more air from the annulus space.The test results on drilling upward and downward holes indicated that the structure of drill bit which has double row with 1 2 suction holes on the spline had the stronger suction capacity and better reverse circulation effect of the slag discharge. Therefore,there was less dust in the cavity and more rock cuttings discharged from the central channel while using type A drill bit.In hence,the reverse circulation discharging effect of type A drill bit is superior to that of type B drill bit.