基于直剪试验的滑带土强度再生特征研究

边坡稳定性主要受控于滑动带或软弱面的强度,选择合适的滑带土强度参数对边坡稳定性分析及防护设计具有直接影响。以三峡库区巴东县某滑坡滑带土为研究对象,对其重塑土样进行了慢剪、渐进剪、反复剪以及固结反复剪等4种剪切试验,研究了在不同试验方案下试样的峰值强度、折减强度以及残余强度的变化。通过试验结果对比分析,发现渐进剪切试验中峰值强度略高于慢剪试验中的峰值强度,并且固结反复剪切试验中的折减强度和残余强度也均高于反复剪切试验中的相应的强度值,揭示了滑带土结构的强度再生现象。同时,基于试验结果的统计分析,探讨了轴向压应力对滑带土结构强度再生的影响,发现在轴向压应力为100k Pa时,滑带土试样强度再生现象最为明显。

Strength regeneration characteristics of sliding zone soil based on direct shear test

The stability of slope is mainly controlled by the strength of sliding zone soil and weak plane. Adoption of appropriate strength parameters of sliding zone soil has a direct impact on slope stability analysis and protection design. Based on the case of a landslide in Badong County of the Three Gorges Reservoir area, four kinds of shear tests, namely slow shear, gradual shear, repeated shear and consolidated repeated shear were carried out, and the peak strength, reduction strength and residual strength of samples under different test schemes were studied. Through comparative analysis on the test results, we found that the peak intensity of the gradual shear test was slightly higher than that of the slow shear test, and the reduction strength and residual strength in consolidated repeated shear test were higher than those in repeated shear test, which revealed the structural strength regeneration of sliding zone soil. At the same time, based on the statistical analysis of the test results, the influence of axial compressive stress on the strength regeneration of the sliding zone soil structure was discussed, finding that the strength regeneration of the sliding zone was obvious at the axial compressive stress of 100 kPa.