软硬岩互层边坡的破坏模式及稳定性研究

采用FLAC^3D强度折减法研究软硬岩互层边坡在不同岩层厚度组合h、不同岩层倾角下边坡的破坏模式和稳定性系数k。结果表明h对边坡的破坏模式影响较小，θ对边坡的破坏模式影响明显①水平层状边坡破坏模式为滑移—压致拉裂;随着θ的增大，顺倾向边坡破坏模式为滑移—拉裂、顺层滑移、滑移—溃曲、弯折—溃曲;直立边坡为弯折—崩塌破坏模式;反倾向边坡为滑移—溃曲和弯折—倾倒破坏模式。②缓倾向顺层边坡中，h的变化对边坡k影响很小，k由靠近坡脚处的软岩决定;其余层状边坡中，当软岩厚度不变时，k随着硬岩厚度的增大而增大，当硬岩厚度不变时，k随着软岩厚度的增大而减小。③随着θ的增大，顺倾向边坡中，k曲线呈现出先减后增的形状;反倾向边坡中，k曲线呈现出先增大后减小再增大的形状;软硬岩互层边坡总体稳定性趋势为，近直立层状边坡>陡倾向顺层边坡>反倾层状边坡>近水平层状边坡>缓倾向顺层边坡。

Numerical Analysis of Failure Modes and Stability of Soft and Hard Rock Interbedded Slope

The failure modes of soft and hard rock inter-bedded slope were simulated by FLAC3D,and the stability coefficient k in the presence of different dip anglesθand rock thicknesses h was analyzed by using strength reduc-tion method.Results show that h has small influence on slope failure mode,whileθhas obvious effect on the failure mode.For horizontally layered slope,the failure mode is slipping-ripping;whereas for consequent slope,with the increase ofθ,the failure mode experiences a progress of sliding-ripping,sliding,sliding-buckling,and bending-buckling;while for vertically layered slope,the failure mode is bending-slump;and for anti-dip rock slope,the failure modes are sliding-buckling and bending-toppling.Moreover,for gentle bedding rock slope,the thickness of the rock has little impact on the stability coefficient k,which is determined by the soft rock near the slope toe.As for the other types of layered slope,when the thickness of soft rock is constant,the stability coefficient increases with the increase of hard rock thickness,while when hard rock thickness is constant,the stability coefficient de-creases with the increase of soft rock thickness.With the increase ofθ,the k value of consequent slope first de-creases and then increases,while the k value of anti-dip rock slope increases and then decreases and finally increa-ses.The overall stability of soft and hard rock slope follows the order of vertical layered slope>steep bedding rock slope>anti-dip slope>horizontal layered slope>gentle bedding rock slope.