mechanical drills meaning in English

坏操练
机械操练

( 3 ) rock bolts are used as an extension of the supporting piles . this structure solves the embedding problem of cantilever pile and is newly applied in foundation trench in china . no environment contamination appears in this old crowed town because no detonation or mechanical drilling
( 3 )利用岩石锚杆作为围护桩的延伸成功地处理悬臂桩嵌固的问题，该结构方式的应用为国内首例，避免了在旧城镇老房屋密集区基岩爆破和机械成孔对周围环境的影响和污染。
On the other hand , the hydraulic performance of the hole , including flow rate coefficient and uniformity of flow rate , have been tested as standards to evaluate the quality of holes punched by laser drilling machine with much better results than that punched by mechanical drilling machine . the shape of holes taken by a microscope photograph can also give detail and well explanations for this test results
对喷孔水力学性能的试验研究表明，本文提出的用喷孔水力学性能指标(流量系数和流量变异系数)来评价微喷带激光打孔机质量的方法是可行的，并证明微喷带激光打孔机的质量明显优于机械打孔的质量，用显微镜观察喷孔的形状的照片也同样证明了这一点。