颗粒组成和基质吸力对残积土抗剪强度的影响
Effect of particle composition and matric suction on shear strength of residual soil
徐明刚 1姚宗健2
作者信息
- 1. 江苏联合职业技术学院南京分院,江苏 南京 210019
- 2. 山东建筑大学 土木工程学院,山东 济南 250101
- 折叠
摘要
花岗岩残积土遇水后基质吸力丧失,强度显著劣化,会引起崩岗、塌陷等地质灾害和工程问题.受风化程度影响,残积土的颗粒组成在垂直方向上存在差异.为研究颗粒组成和基质吸力对非饱和花岗岩残积土力学性质的影响,对5 种不同颗粒组成的残积土进行土水特征曲线测试和不同饱和度下的直剪试验.采用粒组质量分形维数D表征残积土颗粒组成,D随土壤细粒含量的增加而增大.试验结果表明:残积土土水特征曲线受颗粒组成影响;VG模型参数与分形维数D存在良好的线性关系;颗粒组成和基质吸力影响土颗粒的接触方式,进而影响残积土的抗剪强度;残积土的表观内摩擦角φ和表观内聚力c随基质吸力ψ的增大先增大,当基质吸力ψ达到约200 kPa后φ逐渐稳定而c有所减小;残积土的抗剪强度参数可以使用含有分形维数D和基质吸力ψ的经验公式进行预测.研究成果可以为花岗岩残积土分布地区工程设计中的力学强度参数选取提供参考.
Abstract
Granite residual soil can experience significant deterioration in strength when exposed to water,leading to geological hazards and engineering problems such as collapses and landslides.The particle composition of residual soil varies vertically due to weathering,and this study investigated the influence of particle composition and matric suction on the mechanical properties of unsaturated granite residual soil.Five types of residual soil with different particle compositions were tested using soil-water char-acteristic curves and direct shear tests at different degrees of saturation.The fractal dimension D was used to characterize the par-ticle composition of the residual soil,and it was found that D increased with the content of fine particles in the soil.The results show that the soil-water characteristic curve of residual soil is affected by particle composition.The VG model parameters are lin-early related to the fractal dimension D.Particle composition and matric suction affect the contact between soil particles,which in turn affects the shear strength of residual soil.The apparent internal friction angle φ and the apparent cohesion c of residual soil increase with increasing matric suction ψ,and φ gradually stabilizes while c decreases when matric suction ψ reaches about 200 kPa.Empirical formulas that include the fractal dimension D and matric suction ψ can be used to predict the shear strength pa-rameters(φ,c)of residual soil.These research findings can provide reference for the selection of mechanical strength parameters in engineering design in areas with granite residual soil.
关键词
花岗岩残积土/颗粒组成/分形维数/基质吸力/非饱和力学性质Key words
granite residual soil/particle composition/fractal dimension/matric suction/unsaturated soil mechanical proper-ties引用本文复制引用
基金项目
国家自然科学基金青年基金(51308327)
出版年
2024
国家科技期刊平台
NSTL
万方数据