distributions along the surface ABCD ([[sigma].sub.x], [[sigma].sub.y], [[sigma].sub.z]) are presented three-dimensionally in figures 9, 10, and 11.
It can be observed from Figure 2 that the maximum normal stress
value in the fault zone appears at a distance of 100m between the fault zone and origin O; that is, the closest position to the working face.
(2003) found that the major principal stress and the octahedral stresses (both measured at 0.15 m depth) increased with increasing number of wheel passes, while the mean normal stress
([[sigma].sub.m]) remained almost the same.
This study employed a numerical method (FEM) and the transformed cross section method for the analysis of the stiffness and normal stress
of the straight and curved cantilever beams.
In order to investigate the stress transfer under tension, the throughthickness normal strain and normal stress
(y direction) are neglected according to Kamat et al.'s and Nairn and Mendels's shear-lag model (see [1, 6]).
where [[sigma].sub.n] is normal stress
, [tau] is shear stress, [F.sub.n] is normal force, M is torque, and [R.sub.i] and [R.sub.o] are the inner and outer radii, respectively.
Redistribution and magnitude of normal stress
and shear stress around a hole drilled in an isotropic elastic block of rock are shown in Figure 4.
Other researchers [13-15] evaluated the shear strength envelope of expansive soils and concluded that the relationship between the effective normal stress
and shear strength for expansive clays may be linear or bilinear, which depends on the initial void ratio of the tested samples.
The main research objectives of this study are: (1) determining the evolution characteristics of mining stress when the hanging wall and footwall working faces head towards a fault; (2) obtaining the shear stress and normal stress
evolution characteristics when the hanging wall and footwall working faces head towards a fault and further analyze the law of fault activation; (3) reconstructing the energy accumulation and dissipation processes of the fault during the process of the working face heading.
However, in a more detailed perspective, shear strains will influence the normal stress
distribution specified as elastic shear lag, see Figure 1(c).
where P(x) and [sigma](x) are the axial force and normal stress
of the anchorage body at x, respectively.
Two types of stresses (normal stress
[sigma][phi] and shear stress [tau][phi]) can be calculated for RS measurements performed in a given direction [phi] as can be seen in Equation (3).