土质边坡土体抗剪强度室内外试验研究

结合具体的滑坡工程,通过8个现场水平推剪试验和4组室内反复直剪试验研究了滑带土的抗剪强度指标变化规律、含水量变化对土体强度参数的影响、峰值强度和残余强度之间的差异等.试验结果表明,对于渐进式滑坡,坡体一般有足够的时间形成其滑动面,因此这类边坡的稳定性依靠的应该是它的残余强度,而不是峰值强度.同时,含水量的变化对土样抗剪强度有很大的影响,遇水作用后其强度下降很快,并随着含水量的增加,土体的峰值强度降低,剪切变形增加,这些特性对边坡稳定性非常不利.最后,与室内直剪试验相比,现场水平推剪试验更能按土体实际受力情况来确定试验应力路径,能保证土样的原始结构和含水状态,并沿潜在的滑动方向进行大面积剪切,是一种合理有效的试验方法,试验所得结果值与土体真实值较接近,其结果一般对工程设计是可靠的.图9,表4,参7.

Laboratory and Field Testing Study on Shear Strength of Soil Slopes

Based on a practical landslide engineering ,eight horizontal push-shear tests in situ and four teams of repetitive direct shear tests in laboratory were done in order to study the effects of water content on the parameters of shear strength of soil in slide zone and the difference between the peak strength and residual strength. The results show that the progressive slopes have enough time to form a sliding surface so that the stability of this kind of slopes depends on the residual strength, not the peak strength of soil in slide zone. And the results also indicate that the increasing of water content in the soil causes significant decrease of shear strength of soil, which is adverse to the stability of slopes. With the water content increasing, the peak strength also reduces and the shear deformation increases. The horizontal push-shear test in situ can make the stress paths certain according to practical engineering requirement ,and be done under the state of the original structure and water content of soil, which makes it to be a more reasonable , effective and reliable method comparing with the direct shear test in the laboratory.