典型红层滑坡滑带土自愈合效应试验研究

在滑坡稳定性分析和设计计算中往往选用滑带土的残余强度值，但许多研究发现滑带土在稳定期会有自愈合现象发生，表现为抗剪强度的提高。对于以蠕滑为主的红层滑坡，自愈合恢复值应该在滑坡稳定性评价中予以考虑。通过对典型红层滑坡滑带土样进行“剪切―保持―剪切”试验，研究处于残余状态下的剪切面在不同法向应力、不同保持时间下的愈合情况，并进行相应的分析与讨论。试验结果表明：（1）残余状态下的土样在保持一定时间后再次剪切出现明显峰值，证明了剪切面自愈合效应存在，但是继续剪切时恢复的强度随位移快速消失；（2）随着保持时间的增长，剪切面的强度恢复值越来越大；（3）剪切面的自愈合相比法向应力更依赖于保持时间。将得到的摩擦系数值运用断层强度恢复经验公式拟合，提出不同法向应力下常数A的取值，可在滑坡安全系数计算中参考。

Experimental study of self-healing of slip zone soil in typical red bed landslide

In landslide stability analysis and design calculation, the residual strength value of slip zone soil is often selected, but many studies have found that the slip zone soil has self-healing phenomenon in the holding period, which is manifested as the increase of shear strength. For the red bed landslide dominated by creep, the application of recovered strength in the stability analysis of a reactivated landslide should be considered. The shear-hold-shear experiments are carried out on soil samples from a typical red bed landslide to determine the healing of shear zones under different vertical stresses and holding durations. The experimental data show that, the strength recovery occurs in the tests under different pressures, but the recovered strength will lose in very small shear displacement; the strength recovery value of the shear zone becomes larger and larger with the increase of holding time; self-healing of shear zones is more dependent on holding time than vertical stresses. The obtained friction coefficient values is fitted with the empirical formula of fault strength recovery, and the value of constant A under different vertical stresses can be obtained. The value of constant A can be applied to stability analysis of the reactivated landslide.