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雷州半岛玄武岩残积土属于区域性特殊土,全面系统地评价玄武岩残积土的工程地质特性对于该地区建设、地质工程勘察具有重要指导意义。玄武岩残积土是由玄武岩经过长期缓慢的风化分解与红土化作用形成,土层分布具有上细下粗的结构特征。黏土矿物以高岭石类为主,含有较多的游离氧化铁、铝。微观结构以凝块和絮凝结构为主,粒径小于1μm的微孔占总孔隙70%以上。特殊的物质构成与结构形态导致其具有高孔隙率、低密度、高液限的物理特性,但强度较高的力学特征。该土的膨胀性小,但收缩性较大,夯击压实效果差,抗水性差,浸水饱和后力学性质劣化明显,同时对温度与湿度等环境因素敏感,在炎热多雨的气候影响下,颗粒间胶质容易发生脱水老化,导致结构强度减损,微观尺度上结构扰动、破坏,遇水产生严重的崩解现象与较大的湿陷变形,实际工程应关注强收缩势与降雨积水引发的工程灾害。
Basaltic residual soil in Leizhou Peninsula belongs to special regional soil. It is of great significance to evaluate the engineering geological characteristics of basaltic residual soil in a comprehensive and systematic way for the construction and geological investigation in this area. The basalt residual soil is formed by the long-term slow weathering and decomposition of basalt and the lateriteification. The distribution of soil layer has the features of fine structure and fine structure. Clay minerals mainly kaolinite, containing more free iron oxide, aluminum. The microstructure mainly consisted of clots and flocculation structure. The micropores with the diameter less than 1μm accounted for more than 70% of the total porosity. The special material composition and structural morphology lead to its high porosity, low density, high liquid limit physical properties, but high strength mechanical properties. The soil is less expansive, but has more shrinkage, poor compaction effect, poor water resistance and obvious deterioration of mechanical properties after being saturated with water. Meanwhile, it is sensitive to environmental factors such as temperature and humidity. Under the influence of hot and rainy weather, The intergranular gum is prone to dehydration and aging, leading to structural strength loss, structural disturbance and destruction at the microscopic scale, severe disintegration with water, and large deformation of collapsing. Actual engineering should pay attention to the strong shrinkage and the precipitation caused by precipitation Engineering disaster.