Abstract:

In the current code, the E_ak formula for active rock pressure of slopes sliding along gently inclined outward weak structural planes does not consider the water pressure of the trailing edge fractures, which leads to deviation in E_ak calculation. In view of this problem, according to the balance relationship and geometric conditions of the force system, the stress analysis and simplification are carried out considering the water pressure of the trailing edge crack, and the calculation formula of the active rock pressure is derived to determine whether there is an extreme point and its location. The research results show that the error of E_ak is 21.89%-100% without considering water pressure; E_ak has a maximum in the effective range. The dip angle of gently inclined rock stratum θ   and the friction angle in the structural plane φ  are compared, it is found that if θ >φ , the width of potential slip surface at the top of slope is generally 0.2-1.2 times of the slope height H; and if θ  ≤ φ  , the maximum value of E_ak appears on the slope. This study improves the calculation formula by classification, and analyses the correlation between the extreme point position and some factors including H. It is of theoretical and practical significance for the prevention and control of sliding slope along gently inclined soft outward inclined structural plane.

Key words: gently inclined, weak outward inclined structural plane, active rock pressure, fissure water pressure