高温低湿风化环境下残积土性能劣化研究

陈晓贞　黄月明

摘 要：基于福建气候特点及花岗岩残积土的普遍存在，选取福州和泉州两个地区的花岗岩残积土，利用高低温湿热试验箱室内模拟高温低湿湿热环境对两种残积土力学性能的劣化作用。结果表明，两种残积土粘聚力均随高温低湿风化时间的增长而以指数函数形式不断劣化，两种残积土内摩擦角在风化前期基本不变，风化后期泉州残积土内摩擦角开始产生劣化。损伤程度与试样矿物成分及水分蒸发有关。

关键词：花岗岩残积土；高温低湿环境；试验模拟；强度劣化；劣化机理

基金项目：福建省中青年教师教育科研项目资助（编号JA15588）

Abstract： Based on the climatic characteristics and the widespread existence of granite residual soil in Fujian， the granite residual soils in Fuzhou and Quanzhou were selected. The degradation of mechanical properties of two kinds of residual soils in high temperature and low humidity environment was simulated by the useing of high-low temperature-humidity test chamber. The results show that the cohesion of the two residual soils is deteriorated exponentially with the increase of the weathering time. The friction angle of the two residual soils is basically unchanged in the early stage of weathering， and the friction angle of the residual soil in Quanzhou began to deteriorate in the later stage of weathering. The degree of damage is related to the mineral composition of the sample and the evaporation of water.

Keywords： Granite Residual Soil； High Temperature and Low Humidity Environment； Experimental Simulation； Strength Degradation； Deterioration Mechanism

0 引言

环境因素的长期风化作用使岩土体发生物理化学性质变化，影响其力学特性，进而影响结构体的长期稳定性及耐久性。因此，边坡的长期稳定性及抗风化设计是未来岩土工程设计的一个重要内容[1]。福建省地处东南沿海，花岗岩残积土在福建省内广泛分布，湿热环境对边坡花岗岩残积土的物理风化作用普遍存在。而目前对福建省花岗岩残积土的研究仅限于结构及工程特性方面 [2-3]，而对于季节性气候条件作用引起的微观结构的不断演化，导致力学性能劣化的劣化规律及机理的深入系统研究寥寥无几。本文选定福建两个地区花岗岩残积土，根据福建的气候特征，室内模拟高温低湿环境对两种花岗岩残积土力学性能劣化作用。选定抗剪强度指标为损失模量，根据试验结果对比研究两地残积土损失模量随湿热环境作用的变化规律，揭示损伤机理。……