gravel pack是什么意思

用法例句

Reserch on anti-cracking function of big-size gravel;

水泥稳定大粒径砾石的抗裂性能研究

Looks into in the way of the performance on the gravel flexible primary level asphalt pavement route;

砾石柔性基层沥青路面路用性能调查

Based on the water quality and climate of the oil contaminated lake in Daqing area,four simulated subsurface wetland systems were constructed in the field to study their removal effect of oil in lake water,including the gravel bed,the gravel-reed bed,the slag-reed bed and the slag bed.

针对大庆地区石油类化合物污染湖泊水质特点和气候条件,采用包含砾石床、砾石芦苇床、炉渣芦苇床和炉渣床单元的现场试验系统,考察启动期、投加微生物、投加缓释碳源、水温低于5℃和常规运行期等工况下各单元对石油类化合物的去除效果及其去除机理。