干湿和冻融循环作用下泥质白云岩宏观劣化研究

水岩相互作用是岩土工程及相关学科的研究热点。通过干湿和冻融循环试验,对泥质白云岩的力学特性劣化规律及扩容研究,取得了一定的成果。结果表明：(1)泥质白云岩在干湿和冻融循环作用下均会出现明显不均匀的强度劣化。60次循环作用下,干湿循环比冻融循环对岩石的影响更大。(2)冻融循环作用60次的岩样的抗压强度的总劣化度会随围压的增大而增大。(3)干湿和冻融循环作用下,屈服点(扩容点)与峰值点的应力比-围压呈线性关系。(4)60次循环作用下,低围压时,干湿循环岩样的泊松比大于冻融循环下岩样的泊松比,高围压时,冻融循环下岩样变形模量大于干湿循环下岩样的变形模量。

Study on the Macro Degradation of Argillaceous Dolomite under the Dry-wet Cycles and Freeze-thaw Cycles

Water-Rock Interaction is a hot topic in geotechnical engineering and related disciplines. Some achievements have been made in the study on the deterioration of mechanical properties and rock dilatancy of argillaceous dolomite by dry-wet and freeze-thaw cycle tests. The following conclusions are drawn through the analysis of the test results. (1) the strength deterioration of the argillaceous dolomite is obviously uneven under the action of dry-wet and freeze-thaw cycle. Under 60 cycles, dry-wet cycle has a greater impact on rocks than freeze-thaw cycle. The total deterioration of the compressive strength of rock samples subjected to 60 freeze-thaw cycles will increase with increasing in confining pressure. Under the action of dry-wet and freeze-thaw cycles, the stress ratio between the yield point (dilantancy point) and the peak point-confining pressure showed a significant linear correlation. Under sixty times cycles test, when confining pressure is low, Poisson"s ratio of dry-wet cyclic sample is greater than Poisson"s ratio of freeze-thaw cyclic sample. When confining pressure is high, modulus of deformation of freeze-thaw cyclic sample is greater than modulus of deformation of dry-wet cyclic sample.