Discussion on the choice of strength parameters for the analysis of saturated clay under undrained conditions
Song Erxiang1,2 Fu Hao1,2 Lin Shijie1,2 Cheng Xiaohui1,2
1. School of Civil Engineering, Tsinghua University, Beijing 100084, China;
2. Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education, Tsinghua University, Beijing 100084, China
Abstract：With regard to the total stress method for undrained analysis of saturated clay, the Terzaghi's principle of effective stress is interpreted firstly in depth, with emphasis on the distinction between steady pore pressure and excess pore pressure and the distinction between equilibrium total stress containing total pore pressure and constitutive total stress containing only excess pore pressure. When applying the total stress method to undrained analysis of saturated clay, the “total stress” must be the constitutive stress. Furthermore, it is clearly pointed out that the consolidated undrained strength parameters usually should not be used directly in the strength calculation of undrained soil, and the error induced thereby is related with the slope of the total stress path. It is proposed that the unconsolidated undrained strength cu shall be employed, and calculation formulas for determining the strength parameter cu from the consolidated undrained strength parameters are provided. Three typical types of geotechnical problems, namely ground bearing capacity, Rankine's earth pressure and excavation stability, are calculated by using the two types of strength parameters, and the differences in the results are demonstrated and discussed.
宋二祥 付浩 林世杰 程晓辉. 饱和黏性土不排水分析中总应力强度指标的选用[J]. 土木工程学报, 2021, 54(9): 88-95.
Song Erxiang Fu Hao Lin Shijie Cheng Xiaohui. Discussion on the choice of strength parameters for the analysis of saturated clay under undrained conditions. 土木工程学报, 2021, 54(9): 88-95.
