滑带土力学特性是复活型滑坡是否会再次启滑的关键因素之一,以往研究认为滑带土的残余强度是一个静态参数,但近年来不少研究发现滑带土强度在稳定期会产生自愈合现象,导致剪切强度的提高。对于可能发生复活启滑的平推式滑坡,自愈合效应在滑坡稳定性分析中应予以考虑。通过对红层平推式滑坡滑带土进行“剪切-固结-剪切”试验,研究滑带土的残余强度在不同法向应力与不同固结时间下的愈合情况,并进行相应的分析与讨论。试验结果表明:平推式滑坡滑带土存在自愈合效应,滑坡复活启动强度介于其峰值强度和残余强度之间;滑带土的强度恢复率与固结时间成正比,与法向应力成反比;平推式滑坡滑带土的触变性是其强度愈合机制的主要因素,矿物特征则对该机制起了某种程度的强化作用。以此提出,滑带土的强度愈合机制对平推式滑坡的复活启滑具有重要影响。
Abstract
The mechanical properties of slip zone soil play a crucial role in determining whether a reactivated landslide will slide again. In previous studies, the residual strength of slip zone soil has been regarded as a static parameter. However, recent research has revealed a self-healing effect in which the strength of slip zone soil increases in stable period. This self-healing effect needs to be considered in the stability analysis of reactivated translational landslides. In this study, a shear-consolidation-shear test was conducted on the slip zone soil of a red-bed translational landslide. The aim was to investigate the self-healing of residual strength of slip zone soil under different normal stresses and consolidation durations. The findings demonstrate the presence of a self-healing effect in slip zone soil. The initiation strength of reactivated landslide falls between its peak strength and residual strength. Moreover, the strength recovery ratio of slip zone soil is directly proportional to consolidation duration and inversely proportional to normal stress. The thixotropy of slip zone soil in translational landslides is the main factor underlying the strength healing mechanism, with the mineral characteristics contributing to some extent. In conclusion, the strength healing mechanism of slip zone soil significantly influences the reactivation and initiation sliding of translational landslides.
关键词
平推式滑坡 /
滑带土 /
自愈合效应 /
剪切试验 /
残余强度
Key words
translational landslide /
slip zone soil /
self-healing effect /
shear test /
residual strength
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基金
成都理工大学地质灾害防治与地质环境保护国家重点实验室自主研究课题(SKLGP2020Z008);西藏自治区自然资源厅项目(藏财采 20200890-1);四川省科技计划资助项目(2021YFSY0036)
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