The deformation reason can be confirmed as the results of concentrated drainage of valve chamber traffic tunnel by analyzing 3D monitoring data of the slope deformation body surface behind Shawan hydropower house in Muli River.

Then, the paper essentializes the two key problems in the course of building a three-dimensional monitor network: the optimum geometrical graph and the precision distance surveying.

Drill and blast tunneling of Sandouyan Tunnel for Guandi Hydropower Station;