滑坡失稳的预测预报研究是地质工程领域中的一项重要课题，准确地确定预测预报理论模型的参数是实际应用中的难点。在实际滑坡监测中通常可以观察到位移曲线呈现阶梯形，这些阶梯形位移变化点就是滑坡的变形突变点。为研究滑坡变形突变点的变形特征，进行了不同荷载作用下的天然试样以及不同荷载、不同含水率作用下的浸水试样的流变试验，得到了累计位移-时间曲线以及变形速度-时间曲线。依据秦四清的锁固段理论以及速度倒数法滑坡预警模型对试验结果进行分析。研究结果表明：荷载和含水率的变化对模型参数没有影响，模型参数是关于材料属性的函数；变形过程中突变点的变形特征与破坏时的变形特征相似，并且速度倒数法预警模型在突变点和破坏点确定的模型参数基本一致。因此，滑坡监测曲线中早期位移突变点确定的模型参数可以用于确定滑坡破坏时的预警模型。

Forecasting of landslide failure is a significant topic in the field of geological engineering; but it is difficult to accurately determine the model parameters in the practical application. The ladder-shaped displacement curves are generally observed in actual landslide monitoring; and the changing points on the curve represent the mutation points of landslide deformation. To investigate the deformation characteristics at the mutation points in landslide, a series of rheological tests is carried out on natural samples under different loading levels and on immersion samples under different loading levels and with different water contents. The curves of accumulative deformation vs. time and deformation velocity vs. time are obtained. Based on the Qin's locking section theory and the landslide early warning model with inverse-velocity method, the experimental results are analyzed. The results show that the model parameters are independent of the loading level and water content, and are the functions of material properties. The deformation characteristics of mutation points in deformation process are similar to those at failure, and the model parameters of the landslide early warning model based on the inverse-velocity method at mutation point are identical to those at failure point. Hence the model parameters determined by the early mutation point in landslide monitoring curve can be utilized in the early warning for landslide failures.