Characteristics of Apparent Cohesion and Shear Strength of Unsaturated Compacted Lateritic Soils

• Main Authors: Yu-Shiang Jiang, 江宇祥
• Other Authors: Horn-Da Lin
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/26936316032208905303

碩士 === 國立臺灣科技大學 === 營建工程系 === 102 === Lateritic soils are widely distributed in western Taiwan, and most of them are under unsaturated condition. However, present engineering practice still follows the principal of saturated soil mechanics without consideration of the effect of matric suction. The objective of this research is to study the characteristic of apparent cohesion and shear strength of unsaturated compacted lateritic soil. This study conducts a series of laboratory tests using compacted lateritic soils from Linkou. Soil specimens were subjected to drying or wetting using the environmental simulation apparatus. Then, matric suction and unconfined compression strength were measured through the filter paper test and UC test. The relationship between unconfined compression strength and matric suction under drying and wetting path is studied. Moreover, this study also used the results from unconfined compression test and filter paper test to estimate the apparent cohesion. The results were compared with that from unsaturated triaxial tests. The tests results show that there is a positive correlation between unconfined compression strength and matric suction for compacted lateritic soil. The slope of the strength change is greater on the drying path than on the wetting path. Although the apparent cohesion estimated by UC tests seems to overestimate the real apparent cohesion, a reduction correlation exists. Further study is warranted.