两类经典滑坡发生时间预报模型的理论分析

老化和应变速率对土体强度和变形性质的影响研究,以及野外事例观察,已经证实大多数滑坡的形成机制可以由深部蠕变理论解释。土体蠕动速率在滑坡爆发之前将随着造成滑坡因素的增加而增加。根据这一理论,人们可以建立早期滑动的唯象蠕变方程来预测滑坡。早期的这类代表模型是Saito模型和Voight模型。本文重新进行的理论分析表明:这些模型具有丰富的理论内涵和深入的理论基础,具备滑坡预报模型要求的所有条件,包含的参数物理意义明确,因而具有新的生命力。 

THEORETICAL ANALYSIS TO TWO CLASSIC LANDSLIDE PREDICTION MODELS: SAITO'S MODEL AND VOIGHT'S MODEL

Based on the influence of the aging and strain rate of a sloping soil mass on the strength and deformation of the soil mass, as well as the observations of many landslides cases, it has been demonstrated that the mechanism for formation of most landslides can be explained by the deep creep theory. Before a landslide occurs, the creep rate of a soil mass increases with an increase of the factors responsible for the landslide. According to this theory, ones can set up an empirical equation between deformation and time for predicting the time of failure of a landslide. Two earlier typical models are the Saito''s model and Voight''s model. The author has dug out some newly discovered facts hidden in the two models and developed a generalized prediction model, which can be used to forecast a landslide more accurately. Differing from the Saito''s graphic solution method, the author has presented a more convenient technique for estimating the parameters in the equations. The presented method allows the data to be fitted with the presented model and expressed in terms of displacement, through non-linear estimation techniques using the SPRESHEET application software, in order to find values of the controlling parameters(A, B, m, t_f) suitable to represent the mechanical behavior of a large-scale landslide approaching the failure. A simple case study has confirmed the validity of both the presented generalized model and estimation technique through computing the deformation-time curve and defining the time limit or failure time value.