宝鸡地区典型黄土剖面钻孔岩芯工程地质特性研究

摘要

在野外详细调查的基础上,对宝鸡市陈仓区贾村塬典型黄土剖面进行了原状全程取芯钻探工程,并开展了室内系统物理力学参数和物质组成测试分析,以探讨滑坡形成机制.系统的测试分析表明:密度和孔隙比之间成负相关关系；液限和塑限之间呈正相关关系,两者曲线波动的规律基本一致；压缩模量和压缩系数成负相关关系；内聚力和内摩擦角呈负相关的关系,但数据波动较大.典型黄土剖面黄土与古土壤颗粒组成、碳酸盐含量及主要黏土矿物分析表明:0.075～0.0l0mm粗粉土粒含量和碳酸盐含量呈正相关关系,二者与内聚力呈负相关关系,而与内摩擦角呈正相关关系；＜0.002mm胶粒成分主要为伊利石蒙脱石混层矿物,其次为伊利石和高岭石,并与内聚力呈正相关关系,而与内摩擦角呈负相关关系.%A new complete loess profile has been found in Baoji region of the Loess Plateau in recent years. Based on this profile, this paper presents a study of the features of loess engineering geology. The loess is about 200m thick and formed from Holocene epoch to Lower Pleistocene epoch. The study is based on a detailed field investigation of typical loess section at Jiacun Terrace in Chenchang of Baoji region. Borehole drilling in the typical loess layer was conducted. Approximately undisturbed cores were obtained for the entire borehole depth. Subsequently,a systematic laboratory tests were carried out for the physical and mechanical parameters and material formation of the cores. The data was for the analysis of landslide mechanism and prevention. The test results show that 1 ) there is an inverse correlation between density and porosity'ratio,2)there is a positive correlation between liquid limit and plastic limit along with the borehole depth, 3 ) there is an inverse correlation between modulus of compression and compressibility factor, and 4 ) there is an inverse correlation between internal cohension and internal friction angle with large variation range along the borehole depth. The analyses on the grain size analysis, carbonate content and major clay minerals of the typical loess show that a) there is a positive correlation between the 0. 075mm to 0. 010mm grain contents and the carbonate content,b)the grain and carbonate contents have an inverse correlation with the internal cohesion and a positive correlation with the internal friction angle, and c) there is a positive correlation of the less than 0. 002mm colloid particle contents with the mixed-layer mineral of illite and montmorillonite, illite, kaolinite and other major clay minerals, and d) the less than 0. 002mm colloid particle contents also have a positive correlation with the internal cohesion and an inverse correlation with the internal friction angle. The systematic test results presented in this paper will have an important significance to increase the scientific degree and reliability of loess landslide risk assessment.