海岸带花岗岩残积土三轴试验尺寸效应研究

Study on specimen size effect of triaxial test of granite residual soil in coastal zone

随着海洋工程建设深入开展,掌握海洋地质条件下土体的工程特性越发显得重要。本文针对福建平潭地区海岸带的花岗岩残积土,开展了试样直径分别为39.1mm、61.8mm和101mm的常规三轴固结不排水剪切试验,初步探讨了不同试样尺寸对花岗岩残积土的应力-应变特性以及强度的影响。研究结果表明,试样尺寸小的花岗岩残积土三轴试样,其应力应变曲线峰值强度大于尺寸较大的试样;同时,花岗岩残积土的抗剪强度指标也随着试样尺寸的减小而增大。因此,实际工程应用中应注意试样的尺寸效应。

With the development of marine engineering construction,it is more and more important to have a thorough understanding of the engineering characteristics of soils under marine geological condition. The consolidation undrained triaxial shear tests with different specimen diameters,including 39.1 mm,61.8 mm and 101 mm,were conducted on granite residual soil,which came from the coastal zone in Pingtan,Fujian Province. The effects of different specimen sizes of triaxial test on the stress-strain characteristics and shear strength of granite residual soil were discussed. The research results show that the peak strength with smaller specimen is greater than that with larger specimen,and indexes of shear strength,including internal friction angle and cohesion,increases with the decrease of specimen size. The size effect of specimen should be considered in practical engineering application.