川东紫色土及母质水理性研究

Research on water physical property of purple soil and parent material in eastern Sichuan

正确了解和评价紫色土的水理性质,是防止紫色土区产生不良环境问题和工程问题的关键。通过测定川东沙溪庙组、遂宁组、蓬莱镇组紫色土及母质理化参数、黏土矿物成分、母质水分特征曲线以及遂宁组紫色泥岩崩解率随含水量和时间变化规律,比较了3种不同黏粒含量紫色土母质水分特征曲线之间的差异,分析了遂宁组紫色泥岩在不同条件下的崩解特征。结果表明:沙溪庙组、遂宁组、蓬莱镇组紫色土黏土矿物成分主要为水云母,其次是蒙脱石等,不含其他区域紫色土中普遍存在的高岭石和蛭石,主要化学成分中的硅铝比值较其他地区紫色土中的硅铝比值低;不同母质发育而成的紫色土持水率由高到低依次为蓬莱镇组、沙溪庙组、遂宁组;快速崩解是紫色泥岩区紫色土别于其他土壤的特性之一。

Correct understanding and evaluation on water physical properties of purple soil is the key to prevent the adverse en- vironmental impact and engineering problems in purple soil areas. Through measuring and determining the physical and chemical parameters, the clay mineral components, the water characteristic curve of parent material and the disintegration rate of Suining purple mndstone varying with soil moisture and time of purple soil and its parent material from 3 groups of Shaximiao, Suining, Penglaizhen in eastern Sichuan province, we compared the differences in water characteristic curves of purple soil and parent materials containing 3 kinds of clay proportions, and the disintegration characteristics of purple mudstone of Suining Group under different conditions are analyzed. The results show that, the purple clay of the Shaximiao, Suining and Penglaizhen mainly con- tains hydromica and montmorillonite, but does not contain kaolinite or vermiculite which is universally distributed in the purple soil in other areas, and the silica - alumina ratio is lower than that in other purple soil areas; the water holdup of purple soil derived from different parent materials varies from high to low as： Penglaizhen, Shaximiao, Suining; the rapid disintegration of purple soil is the most significant feature distinguished with other soil.