通过对新疆和甘肃地区戈壁碎石土地基现场分层直剪试验，研究了其抗剪特性和强度参数的取值。试验结果表明：戈壁碎石土地基具有较好的抗剪承载性能，正应力作用下其抗剪承载过程可分为弹性变形、弹塑性至峰值强度、强度软化至残余强度3个阶段；戈壁碎石土地基内摩擦角的均值、标准差和变异系数分别为40.6°～43.6°、3.4°～10.3°、0.003～0.253，黏聚强度的均值、标准差和变异系数分别为10.5～23.0 kPa、1.2～7.3 kPa、0.12～0.33；黏聚强度的标准差和变异系数均有随黏聚强度均值的增大而增大的趋势。研究成果可为我国戈壁地区掏挖基础工程应用及其设计优化提供参考。

Field direct shearing tests on Gobi gavel soil are carried out in Xinjiang and Gansu province, where the shear characteristics and strength parameters are discussed. It is indicated that the Gobi gravel soil is of great shear capacity, of which the shear process under normal stress could be described as three stages including elastic deformation, elastic-plastic deformation to peak strength and strength demineralization to residual strength. The mean value, standard deviation and coefficient of variability for the internal friction angle of Gobi gravel soil are 40.6°~43.6°, 3.4°~10.3°and 0.003~0.253, while those for cohesive strength are 10.5~23.0 kPa, 1.2~7.3 kPa and 0.12~0.33 respectively. Moreover, the standard deviation and coefficient of variability for cohesive strength increase with increasing mean value. The results obtained in this paper can provide references for engineering application and optimized design in Gobi areas.