2) feedback and expanding roadway
回撤扩帮
1.
This method with a simple production system,is of lower cost But problems such as methods of tunnel support and feedback and expanding roadway,and designs of ratio of extraction to reservation,should be still studied in the extraction through tunnel.
但其巷道支护方法、回撤扩帮方法和采留比设计等,仍是巷道穿采中值得深入研究的问题。
3) borehole enlargement by drawing back
回拖扩孔
4) sudden-expansion recirculating flow
突扩回流
1.
The predictions for the two-phase flows indicate that,compared with the sudden-expansion recirculating flow, the largevelocity-difference-jet recirc.
本文建立了气－固两相流的多连续介质模型，并分别对突扩回流与大速差射流回流这两种与实际工程应用密切相关的复杂流动条件下的受限湍流气一固两相流动进行了数值模拟。
5) back reaming
回扩钻进
6) back reamer
回扩钻头
1.
The paper dis- cussed the main technical points of bedrock drilling,the design and selection of back reamers for different formations and drilling diameters,detailed construction technology of bedrock with typical engineering cases in China and prospected the future development.
论述了非开挖基岩钻进的技术要点及在不同地层、不同管径施工条件下对非开挖回扩钻头的设计及选用。
2.
The improved back reamer is in favor of rock cutting,taken effects on drilling guiding and stabilizing,low cutting resistance,high strength,and good wear resistance,thus have improved drilling efficiency greatly.
针对导向钻进非开挖铺设地下管线施工中回扩钻头存在的口径大、包泥堵钻、进尺缓慢、切削齿不耐磨等问题,对钻头结构进行了研究,并从导向钻头、出水口、刮刀、切削齿等四个方面对钻头进行了改进。
补充资料：三一回五一回
1.犹言三番五次。
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条