梧州市巨厚层花岗岩风化壳垂直分带标准及工程地质特征研究

    VERTICAL ZONING CRITERIA AND ENGINEERING GEOLOGICAL CHARACTERISTICS OF SUPER-THICK LAYER GRANITE WEATHERING CRUST IN WUZHOU CITY

    • 摘要: 本文选择华南地区巨厚层花岗岩风化壳分布区的梧州市为研究区,旨在建立系统的、科学的、可操作性强的花岗岩风化壳垂直分带划分标准。在野外区域调查、钻探、原位试验、室内试验、综合研究的基础之上,建立了定性与定量复合判定的指标体系,对梧州市花岗岩风化壳进行了垂直分带以及工程地质特征研究。研究结果表明:(1)粒度分析法可以作为花岗岩风化壳垂直分带划分的方法之一,划分结果与原位试验划分结果具有很好的一致性;(2)残积土带、全风化带、强风化带中含量占比最大的土体分别是黏粒土、粉粒土、砂粒土。随着钻孔深度的增加,粒径相对较大的砾粒和砂粒含量占比逐渐增大,粒径相对较小的粉粒和黏粒含量占比逐渐减小。粒径0.05 mm为残积土带、全风化带、强风化带曲线交叉的分界处,该处土体含量百分比近似相等,揭示粒径0.05 mm值是花岗岩风化壳垂直分带划分的重要指标之一;(3)随着钻进深度的增加,圆锥动力触探试验击数与标准贯入试验击数同时增加,修正后的标准贯入击数N和圆锥动力触探击数N63.5呈多项式相关性。本文建立了花岗岩风化壳垂直分带划分标准,给出了花岗岩风化壳土体地基承载力建议值,对花岗岩分布区的重大工程建设与工程地质特征参数的选取具有一定的指导与参照意义。

       

      Abstract: Wuzhou City is the distribution area of the granite weathering crust with huge thickness in South China. It is selected as the study area. The study aims to establish a systematic,scientific,and operable standard for the vertical division of granite weathering crust. On the basis of field investigation,drilling,in-situ test,laboratory test,and comprehensive research,an index system of qualitative and quantitative composite judgment is established. The vertical zoning and engineering geological characteristics of granite weathering crust in Wuzhou City are studied. The studies show that: (1) Granularity analysis can be used as one of the methods of vertical zoning of granite weathering crust. The division results are in good agreement with the results of the in-situ test division. (2) Clay,silt and sand soil account for the largest proportion in residual soil zone,completely weathered zone and strongly weathered zone,respectively. The size of soil particles increases with increasing depth. The proportion of gravel and sand particles with relatively large particle sizes gradually increases. The proportion of powder and clay particles with relatively small particle sizes gradually decreases. Particle size 0.05mm is the boundary of curve intersection of residual soil,fully weathering zone and strongly weathering zone. The percentage of soil content at this place is approximately equal,revealing that the value of 0.05mm particle size is one of the important indicators for the vertical division of granite weathering crust. (3) With the increase of the drilling depth,the number of cone dynamic penetration test hits and the number of standard penetration tests increase simultaneously. The corrected standard penetration number N and cone dynamic penetration penetration number N63.5 show a polynomial correlation. In this paper,the standard of vertical zoning of granite weathering crust was established,and the recommended value of the bearing capacity of the granite weathering crust soil is given,which had certain guiding and reference significance for major project construction and selection of engineering geological characteristic parameters in granite distribution area.

       

    /

    返回文章
    返回