湿热环境下边坡残积土性能劣化研究

Deterioration of Soil Properties in Residual Soil Slopes under Humid and Low Temperature Environment

福建省地处东南沿海地区,湿热环境对边坡残积土的物理风化作用普遍存在,并将影响其力学特性,进而影响边坡的长期稳定性及耐久性。分别选取福州和泉州的两个边坡的花岗岩残积土,利用高低温湿热试验箱室内模拟低温高湿湿热环境对两种残积土试样力学性能的劣化作用。结果表明,低温高湿风化环境下,两种残积土内摩擦角φ基本不变,粘聚力c和抗剪强度τ都随风化时间t增长而以指数函数形式不断劣化。损伤程度与试样低温收缩特性及矿物成分有关,且福州残积土的力学性能损伤程度略大于泉州残积土的损伤。

Fujian Province is located in the southeast coast of China.Under the humid tropical environment,the weathering of residual soil slopes is common.The weathering will adversely affect mechanical properties of residual soils and further affect the long-term stability and duration of the residual soil slopes.The typical granitic residual soil samples from Fuzhou and Quanzhou were collected and the laboratory simulations of weathering conditions on soil sample from both areas were performed in the test chamber that both the humidity and temperature could be controlled.The effect of low temperature and high humidity environment on the deterioration of the shear strength properties of residual soil samples was investigated.The test results indicate,under the laboratory test conditions,the internal friction angles for both residual soils remained approximately unchanged.The shear strength and the cohesion of soil samples from both areas are reduced in power relationship with time.The degree of strength reduction and the contraction characteristics under low temperature conditions are related to the mineral composition of the soil samples.The weathering deterioration in Fuzhou soil samples is slightly greater than those sample from Quanzhou area.