文章摘要
娜荷芽, 魏玉杰, 陈敏, 丁树文, 蔡崇法, 李依潺, 宋萍.鄂东南崩岗区花岗岩风化岩土体抗剪强度的异向性[J].水土保持学报,2019,33(6):113~119
鄂东南崩岗区花岗岩风化岩土体抗剪强度的异向性
The Anisotropy of Shear Strength for Granitic Soils in Collapsing Gully Erosion Area of Southeastern Hubei
投稿时间:2019-05-23  
DOI:10.13870/j.cnki.stbcxb.2019.06.016
中文关键词: 崩岗  抗剪强度  异向性
英文关键词: collapsing gully  shear strength  anisotropy
基金项目:国家自然科学基金项目(41807065)
作者单位E-mail
娜荷芽1, 魏玉杰1,2, 陈敏3, 丁树文1,2, 蔡崇法1,2, 李依潺3, 宋萍3 1. 华中农业大学资源与环境学院, 武汉 430070

2. 农业部长江中下游耕地保育重点实验室
, 武汉 430070

3. 长江水利委员会水土保持监测中心站
, 武汉 430010 
wyj@mail.hzau.edu.cn 
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中文摘要:
      旨在从岩土力学性质的角度为崩岗侵蚀提供理论依据,采用直接剪切实验,对鄂东南崩岗区典型花岗岩风化岩土体剖面不同方向上原状土的抗剪强度进行测定,并分析了花岗岩风化岩土体抗剪强度在剖面尺度上的异向性及其影响因素。结果表明,饱和条件下,花岗岩风化岩土体黏聚力和内摩擦角的变化范围分别为3.19~19.26 kPa和26.50°~32.42°,其中B2层黏聚力最大,而各层次间内摩擦角的差异并不明显(p>0.05);黏聚力和内摩擦角均存在明显的异向性,其中水平方向总体大于垂直方向,且黏聚力的异向性较内摩擦角更明显。不同方向上抗剪强度的影响机理不同,其中,垂直于剖面方向上,黏聚力主要受毛管孔隙度(r=-0.97,p<0.01)和粉粒含量(r=0.94,p<0.05)的影响,而水平方向上仅与粉粒含量(r=0.91,p<0.05)显著相关;而液限对水平方向上的内摩擦角影响显著(r=-0.99,p<0.05)。对于花岗岩风化岩土体抗剪强度的异向性而言,其主要受自然含水率(r=-0.98,p<0.01)、有机质(r=-0.93,p<0.05)和塑限(r=-0.97,p<0.05)影响。研究结果对于从力学稳定性角度揭示崩岗的发生机理具有重要意义。
英文摘要:
      To reveal the mechanism of collapsing gully erosion from a perspective of soil mechanic, the anisotropic characteristics of shear strength and the related influencing factors for undisturbed granitic soils from a typical granite weathered soil profile in southeastern Hubei were investigated by direct shear test. In accordance with the obtained results, the cohesion and internal friction angle of granite weathered soils ranged from 3.19 kPa to 19.26 kPa and 26.50° to 32.42° at saturation, and the maximum cohesion occurred for soils in the B2 layer, while the difference of the internal friction angle along the investigated soil profile was less significant (p>0.05).In addition, cohesion and internal friction angle with significant anisotropy were larger in the horizontal direction than those in the vertical direction. Soil physicochemical properties that influencing of shear strength varied with profile direction. Specifically, the cohesion was mainly affected by capillary porosity (r=-0.97, p<0.01) and silt content (r=0.94, p<0.05) for soils in the vertical direction, and it was conditioned by silt content (r=0.91, p<0.05) for soils in the horizontal direction. However, the significant correlation between soil physicochemical properties and internal friction angle was solely observed for soils in the horizontal direction in which the variation of internal friction angle was influenced by liquid limit (r=-0.99, p<0.05). Furthermore, the anisotropy of shear strength of granitic weathered soils was mainly affected by natural water content (r=-0.98, p<0.01), organic matter (r=-0.93, p<0.05), and plastic limit (r=-0.97, p<0.05). These results would facilitate the understanding about the formation and development of collapsing gully erosion in southeastern China.
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