三峡库区滑坡堆积体非饱和土的土——水特征研究

滑坡堆积体在自然界广泛分布,在三峡库区尤为常见。据统计,三峡库区滑坡体多为不同类型的土石混合物所组成。研究滑坡堆积体的土—水特征对三峡库区地质灾害防治与土木工程建设具有重要价值。采用室内压力板试验仪,重点分析碎石粒径大小、碎石含量、颗粒级配、干密度以及土的塑性指数对滑坡堆积体的土—水特征曲线的影响,并基于Fredlund-Xing(FX3)模型采用SPSS软件回归分析得出简便的计算三特征参数的函数。分析表明:碎石颗粒较小、碎石含量较大两因子相比干密度较小、塑性指数较小两因子对滑坡堆积体的土—水特征曲线的影响具有相同趋势。碎石级配较好的滑坡堆积体有利于脱水,进气值一般较大。非饱和滑坡堆积体的土—水特征曲线的预测方法应用简便,具有一定实用性。

Study on soil-water characteristics of unsaturated soil of landslide deposits in Three Gorges Reservoir Area

Landslide deposits are widely distributed in nature， especially within the Three Gorges Reservoir Area. Statistically， most of the landslide bodies within the Three Gorges Reservoir Area are composed of various types of soil-stone mixtures. The study on the soil-water characteristics of landslide deposit has an important value for the geohazards prevention and the civil engineering construction in the reservoir area. The impacts from particle size of crushed stone， crushed stone content， grain gradation， dry density and soil plasticity index on the soil-water characteristics of landslide deposit are emphatically analyzed with the indoor pressure-plate apparatus， and then the functions for simply calculating the three characteristic parameters are obtained by the regression analysis with SPSS software based on Fredlund-Xing（FX3）model. The analysis shows that if compared with the two factors of lower dry density and the lower plasticity index， the impacts from the two factors of the smaller crushed stone grain and the larger crushed stone content on the soil-water characteristics of landslide deposit have the same trends. The landslide deposit with better gradation of crushed stone is favorable for dewtering， of which the air entry value is normally larger. Generally， the application of the prediction method of soil-water characteristic curve of unsaturated landslide deposit is convenient and simple， thus has a certain practicality.