Question Statement:
In soil dynamics applied to tillage tools, which of the following statements is/are correct based on Terzaghi and Hettiaratchi-Reece passive earth pressure theories?
Options:
- (A) The theoretical failure plane angle $\beta$ in front of a flat inclined tillage blade is given by $\beta = 45^\circ - \phi/2$, where $\phi$ is the internal soil friction angle.
- (B) Soil adhesion ($c_a$) and soil-metal friction angle ($\delta$) significantly influence the interface resistance along the tool surface.
- (C) For narrow tillage tines (aspect ratio width/depth lt; 0.5$), three-dimensional crescent soil failure dominates over two-dimensional plane strain failure.
- (D) Saturated soil shear strength is strictly governed by hydrostatic pore water suction alone with zero cohesion.