温度对饱和红黏土固结和剪切特性的影响

    EFFECT OF TEMPERATURE ON THE ISOTROPIC CONSOLIDATION AND SHEAR CHARACTERISTICS OF SATURATED LATERITIC CLAY

    • 摘要: 伴随着西南地区地热资源的开发与利用,温度变化将引发土体工程特性的改变,开展不同温度下红黏土固结和剪切行为的研究具有重大意义。本文采用温控三轴装置开展一系列温控三轴固结和温控三轴剪切试验,分析了温度对饱和红黏土固结和剪切行为的影响。研究表明,在热固结过程中,压缩指数和回弹指数基本不受温度变化的影响,而先期固结压力随着温度的升高而减小;降温会引起红黏土吸水膨胀,升温会引起红黏土失水收缩,但热致体积应变的大小与围压无正相关关系,并且热固结后会有残余的热致孔隙水压力无法消散,其大小随着围压的增大而增加。在剪切过程中,小应变割线模量和抗剪强度随着温度的升高而增大,归结于温度升高导致土体黏聚力的增加,而内摩擦角和临界状态线斜率的改变并不显著。

       

      Abstract: With the development and utilization of geothermal resources in Southwest China, temperature-induced changes in soil engineering properties have become increasingly significant. Investigating the consolidation and shear behavior of lateritic clay under varying temperatures is of strategic importance. In this study, a series of temperature-controlled triaxial consolidation and shear tests were conducted using a temperature-controlled triaxial apparatus to analyze the effects of temperature on the consolidation and shear behavior of saturated lateritic clay. The results indicate that the compression index and swelling index are essentially unaffected by temperature changes, whereas the preconsolidation pressure decreases with increasing temperature during thermal consolidation. Cooling causes lateritic clay to swell, while heating leads to contraction, though the magnitude of thermally induced volumetric strain is not positively correlated with confining pressure. Thermally induced residual pore water pressure persists after thermal consolidation and increases with higher confining pressure. During shear, the small-strain secant modulus and shear strength increase with rising temperature, which is attributed to increased cohesion. In contrast, the internal friction angle and critical state line slope show no significant changes with temperature.

       

    /

    返回文章
    返回