干湿循环条件下重塑黄土强度与持水特性的试验研究  

Experimental Investigation in Strength and Water Retention Behaviors of Remolded Loess Under Drying-wetting Cycle

作　　者：赵俊宇 许增光[1] 柴军瑞[1] 覃源[1] 张昭[2] ZHAO Jun-yu;XU Zeng-guang;CHAI Jun-rui;QIN Yuan;ZHANG Zhao(State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China,Xian University of Technology,Xian 710048,China;Institute of Geotechnical Engineering,Xian University of Technology,Xian 710048,China)

机构地区：[1]西安理工大学西北旱区生态水利国家重点实验室,陕西西安710048 [2]西安理工大学岩土工程研究所,陕西西安710048

出　　处：《水电能源科学》2021年第9期169-172,139,共5页Water Resources and Power

基　　金：国家自然科学基金项目(51922088)。

摘　　要：库水位升降使得库岸边坡经受反复干湿循环的影响,土的强度与持水特性会随之产生不可逆转的变化。为此,通过对重塑黄土进行反复干湿循环下的直剪、离心和核磁试验,综合分析了土样强度特性、持水特性及孔隙特性的相互影响规律。结果表明,经过3次循环土样抗剪强度具有稳定趋势,粘聚力幂函数趋势减小,内摩擦角线性减小。干湿循环会增大持水曲线的初始饱和含水率与失水速率。第1次循环时基质吸力增大明显,2次循环后持水曲线相对稳定。核磁试验测得土中孔隙含量先快后慢增长,且第2次干湿循环峰谱达到最高。最后对比分析了孔隙—水力—强度的相互影响机制,指出孔隙变化是持水特性和强度参数劣化的内在原因。The rise and fall of reservoir water level makes the slope of the reservoir bank undergo repeated dryingwetting cycles,and the strength and water retention behaviors of the soil will change irreversibly.Therefore,through the direct shear,centrifugal and nuclear magnetic resonance tests of remolded loess under repeated drying-wetting cycles,the interaction laws of strength characteristics,water retention characteristics and pore characteristics of soil samples were comprehensively analyzed.The results show that after three cycles,the shear strength of soil samples has a stable trend,the cohesion power function decreases,and the internal friction angle decreases linearly.Drying-wetting cycles will increase the initial saturated water content and water loss rate of water retention curve.The matric suction increases significantly in the first cycle,and the water retention curve is relatively stable after the second cycle.The results of nuclear magnetic resonance test show that the pore content increases rapidly and then slowly,and the peak spectrum of the second drying-wetting cycle reaches the highest.Finally,the interaction mechanism of pore-hydraulic-strength is compared and analyzed,and it is pointed out that pore changes are the internal reason for the deterioration of water retention characteristics and strength parameters.

关 键 词：黄土 干湿循环 抗剪强度 持水曲线 孔隙 

分 类 号：TU411[建筑科学—岩土工程]