广西红粘土和膨胀土土热力学特性的比较研究

基于广西膨胀土和红粘土的成因类型、物质成分和结构特征,研究常温(-4℃～60℃)下膨胀土与红粘土的热力学特性,探讨了红粘土与膨胀土的抗剪强度指标与温度之间的相关关系。试验结果表明,两种土在10℃,40℃与室温(28℃)时,主应力差σ1-σ3峰值变化不大,而60℃时有明显增大;在相同条件下,红粘土的主应力差峰值变化更大;红粘土与膨胀土的抗剪强度指标(c,φ)随热状况不同而发生变化,而且红粘土的粘聚力c和膨胀土的内摩擦角φ在室温,环境有较小值。分析结果认为,两种土的热效应影响趋势相似,但红粘土的热力学特性较为敏感,这与红粘土的成因类型及胶结特征密切相关。研究结果为红粘土与膨胀土地区工程建设及减灾防灾提供参考。

Comparative study on thermodynamics characteristics of red clay and expansive soils in Guangxi

Based on analyzing the causes of information, material components and structural characters of the common expansive soil and the red clayed soil in Guangxi, some thermodynamics tests have been done on the red clayed soil and the expansive soil under normal temperature (-4 ℃-60 ℃) to search their thermodynamics characters and their relations between shear strength index and temperature. According to the tests,（σ1-σ3）peak value of the two kinds of soils do not change much under the indoor temperature (28 ℃) and the temperature of 10 ℃, 40 ℃ environment respectively, while under the temperature of 60 ℃ the change is obvious. Under the same conditions the main difference stress peak value of the red clayed soil has a greater change. The shear strength indices c,φ of two soils change with the hot state accordingly. Furthermore, the cohesive stress c of the red clayed soil and the friction angle φ of the common expansive soil are less relatively in the indoor temperature environment. From the tests we can conclude that the tendency of the thermodynamic influence on the red clayed soil and the expansive soil is similar, but the red clayed soil is more sensitive to the thermodynamic change. All these differences are caused by the genetic type and agglutinate character of the common clayed soil. The result of study offers reference for reducing the disasters and taking precautions against the calamities so as to help the construction on the red clayed soil and expansive soil area.