柳州市酸雨对红粘土工程地质性质影响机理

A MECHANISM ANALYSIS OF ACID-RAIN'S EFFECTS UPON THE ENGINEERING GEOLOGICAL PROPERTIES OF RED CLAY IN LIUZHOU CITY

柳州市红粘土的分布约占市区总面积的５０％．在酸雨的作用下，其工程地质性质发生改变，致使其含水性、可塑性和压缩性增大，密实性、抗剪强度和承载力降低。造成这种不良影响的机理主要是：酸雨对红粘土中难溶盐颗粒的溶解，使土体粒径变小，比表面积增大，使其含水性、可塑性和压缩性增大；酸雨对土体胶结物的溶蚀，使土体原有结构发生破坏，从而降低土体的抗剪强度；酸雨使土体产生离子交换作用，改变了土粒原有双电层结构，致使土体的工程地质性质发生改变。但由于土体对酸雨具有较大的缓冲作用，在短时期内还不会造成大的危害。

About 50 Percent of the Liuzhou city′s ground are covered with the red clay,and its engineering geological properties are changed under the influence of acid-rain. Its nature of moisture, plasticity and compressibility increase, wherasle its compactness, shear and bearing capacity decrease. The following is considered to be the main mechanism of the bad effectS after the research op the insoluble salt in the red clay can be dissolved by the acid-rain, which can made the grain size of soil mass smaller, the specific surface area bigger, and the nature of moisture, the Plasticity and the compressibity increased; The acid-rain can also corrode the cementing material of soil mass and discompose the original structure of soil mass, so the shear strength of soil mass decreases. The soil mass can produce the ionic exchange under the influence of the acid-rain, and the original structure of the electric double layer of Particle can be change and thus can make the engineering geological Properties of soil mass change.However, there won′t be much serious endangers during short time due to the buffer action of soil mass upon the acid-rain.