If the truedip line of one or two joint planes plot within a sliding zone of double-faced slope, a double-faced sliding failure can be possible.
如果有一两个节理面真倾向线落在滑动区内，滑动破坏才可能发生。
2
True, Apple’s relative success is partly due to a dip in the oil price, which has pummeled Exxon’s shares, and to the volatility that swept through stockmarkets this week.
On condition that we have known the true azimuth of the tunnel and determined only two false dip in the tunnel, the attitude value has gotten by simple computation.