The holesealing agent has the advantages of simple construction, low difficulty to master, good sealing effect, safe use and low cost, etc.
本发明具有施工简单、易于掌握、封堵效果好、使用安全等优点，且成本低廉。
2
It describes the improvement scheme, and emphatically introduces the selections of open holesealing equipment. Therefore it has a certain reference value.
简述了整改方案，重点介绍了开孔封堵设备的选用，具有一定的借鉴作用。
3
In 1987, a team from the National Geographic Society drilled a hole through one of the limestone blocks sealing the chamber from above, and inserted a video camera.