委内瑞拉北部铁路膨胀土特征分析

Swelling Soil Characteristics Analysis of Northern Railway in Venezuela

委内瑞拉北部铁路Tinaco-Anaco段是中国高速铁路走向世界的重要工程,北部铁路横穿的奥里诺科平原覆盖着具有膨胀性的粘土、页岩地层,沿线的不良工程地质现象中以膨胀土最为典型。文中对委内瑞拉的膨胀土判别方法进行了介绍,以北部铁路260～360 km段的膨胀土为典型代表分析委内瑞拉北部平原膨胀土的特性,通过采用塑性指数判别法、活性指数图表法、膨胀指数判别法对膨胀土的膨胀活性、膨胀潜力等进行分析,认为该地区的膨胀土具有典型的中～强膨胀性,并分析所带来的工程地质问题,对北部铁路的路基填筑、边坡开挖、桥梁桩型提出了相应的工程措施建议,为委内瑞拉北部平原的铁路设计、施工及其他土木工程提供一定的借鉴意义。

Venezuela Northern Railway Tinaco-Anaco Section is an important project for Chinese high-speed railway promotion to the world. The railway across the Orinoco plain is covered with the swelling clay and shale. The swelling soil is the typical negative engineering geological problem in the Tinaco-Anaco Section. In this paper,we introduce the distinguishing method of swelling clay in Venezuela,and select the swelling clay at 260 km to 360 km in Northern Railway as a typical representative of Venezuela northern plain to analyze its characteristics. We use plastic index criterion,expansive activity index map and expansive index method to analyze the expansive activity and expansive potential. Through the above analysis,we consider the swelling clay belongs to the middle to strong expansion. Finally,we offer proposals for subgrade filling,slope excavation and bridge pile type,and come up with corresponding measures to control the engineering geological problems caused by swelling clay. These discussions can provide reference to the design and construction for Northern Railway and other civil engineering activities in the northern plain of Venezuela.