The Shear Strength of the Nature Loess Joint: A Case Study in Shaanxi Province

摘要

Shear strength of the loess joint has significant influence on the stability of loess engineering with joints. "Joint" is the weak structural plane of loess, and its shear strength determines the stability of loess. In this study, a series of loess joint samples was collected from Binxian County, Liquan County, and Zichang County in Shaanxi Province. The shear strength of the loess joint was determined by means of the direct shear test. The influence of the water content on the shear strength parameters of the loess joint was investigated by means of tests. The results showed that initially the internal friction angle varied slightly with the water content but decreased very quickly as the water content surpassed the threshold value of 14 %. The relationship between shear strength and water content can be expressed as an exponential function. This study devised a new empirical formula that determines the peak internal friction angle by observing the effects of dry density, water content, shear strength, and joint surface morphology.