冻融循环作用下白云岩边坡的稳定性分析

为了探究季冻区白云岩边坡在冻融循环作用下的失稳机理，通过白云岩完整岩样的室内快速冻融循环试验、声速测试试验和单轴压缩试验，获得了不同循环次数后岩块的物理力学性质参数，结合广义Hoek-Brown岩体强度准则，利用冻融岩样的纵波波速量化冻融裂隙岩体的地质强度指标GSI和冻融扰动因子Dn，实现了将岩块的冻融力学参数向边坡裂隙岩体冻融力学参数的转化，并分析比较了岩体各参数的冻融劣化效应，最后以河北省北部山区某白云岩高边坡为背景，利用FLAC3D分析了边坡在冻融效应下的循序破坏机理。结果表明：边坡岩体的各项力学性质参数在冻融作用下均呈指数型下降趋势，其中岩体破碎度的冻融劣化效应最强；剪切塑性区主要在边坡的冻融层中产生和扩展，坡脚处的受损和变形最严重，边坡冻融破坏模式主要为表层碎裂岩块的崩落和沿冻融交界面的浅层滑塌。可见，冻融白云岩边坡的防护方案宜优先考虑从提升岩体完整性的角度入手并选用施工扰动较小的支护体系，以避免因施工扰动而造成浅层风化堆积体的滑塌。

Stability Analysis of Dolomite Slope with Freeze-Thaw Cycles

In order to find out the instability mechanism of dolomite rock slope under freeze-thaw cycles in the seasonal freeze-thaw area. Through the indoor rapid freeze-thaw cycle test, rock acoustic test and uniaxial compression test of the complete dolomite rock samples , the physical and mechanical properties of rock samples were obtained after different cycles. Combine the generalized Hoek-Brown strength criterion , and the longitudinal wave velocity of rock samples was used to quantify the geological strength parameter GSI and disturbance factor Dn of freeze-thaw fractured rock mass, then the transformation of freeze-thaw mechanical parameters of rock to mechanical parameters of slope fractured rock mass was realized, and the deterioration effect of rock mass parameters with freeze-thaw cycle were analyzed and compared. Finally, based on a high dolomite slope in the northern mountainous area of Hebei Province, the sequential failure mechanism of the slope under the action of freeze-thaw effect was analyzed by FLAC3D. The results show that the mechanical properties of rock mass of the dolomite slope show an exponential decline trend under the action of freeze-thaw, among which the freeze-thaw deterioration effect of rock mass fragmentation is the strongest. The shear plastic zone is mainly generated and expanded in the freeze-thaw layer of the slope, and the damage and deformation are most severe at the foot of the slope. The slope freeze-thaw failure modes are mainly the collapse of surface fragmented rock blocks and shallow collapse along the freeze-thaw interface. It can be seen that the protection scheme for the freeze-thaw dolomite slope should be considered from the perspective of improving the integrity of the rock mass and selecting a support system with less construction disturbance, so as to avoid the collapse of the shallow weathered deposits body by construction disturbance.