炭质泥岩土石混合料大型直剪试验研究

Large-Scale Direct Shear Test on Carbonaceous Mudstone Mixtures

炭质泥岩是一种特殊的泥岩,西南地区炭质泥岩土石混合料广泛分布。通过对不同炭质泥岩含量试样的大型直剪试验,研究了30%、60%、100%三种含量的炭质泥岩土石混合料抗剪强度指标的变化规律,并对天然和饱和两种状态下炭质泥岩土石混合料进行大型剪切试验研究,试验结果表明:相同法向应力下,炭质泥岩含量越大,抗剪强度越大;随着炭质泥岩含量的增大,混合土石料的内摩擦角变小,内聚力变大;天然状态的剪应力随着水平位移增大而增加,没有明显的峰值,而饱和状态的剪应力与水平位移关系曲线趋于水平。

The carbonaceous mudstone is a special soft rock that is widely distributed in Southwestern China. The carbonaceous mudstone aggregate mixtures samples are tested by a large size direct shear test device under both saturated and unsaturated conditions. The aggregate mixtures have three different carbonaceous mudstone contents： 30%, 60% and 100%. The test re- sults indicate that, under the same vertical stress, the shear strength increases with the increase of carbonaceous mudstone con- tents. With the increase of carbonaceous mudstone contents, the internal friction angle decreases and the cohesion values in- creases. The shear stress increases with the increase of the horizontal displacement and no obvious peak values are observed. Under the saturated condition, a flatter shear stress and horizontal displacement relationship can be found.