In 1972 UNICEF initiates a project to install tube Wells that pull pure underground water to the surface.
1972年联合国儿童基金会启动一个项目旨在打口深井并将纯净的地下水引到地表。
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The authors described the structure of a newly - developed wedge-tube bolt, its reinforcement principles and anchoring performance, and the results of in situ pull test and productive applications.