多次干湿循环后原状和重塑黄土的持水性试验研究
Water retention behaviours of intact and recompacted loess exposed to multiple wetting-drying cycles
张小辉 1王勇华 1张登飞 2杨丽娜 1卜崇鹏 1王明皎1
作者信息
- 1. China JK Institute of Engineering Investigation and Design Co.,Ltd.,Xi'an 710043,China;Shaanxi Key Laboratory for the Property and Treatment of Special Soil and Rock,Xi'an 710043,China
- 2. State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069,China
- 折叠
摘要
干湿循环的风化作用是引发中国黄土地区基础设施破坏的重要影响因素.黄土的持水性能是此类黄土工程问题物理成因的关键物性.为了探究在干湿循环的环境驱动作用下不同地区原状和重塑黄土的持水性能及其变化规律,利用压力板仪和电镜扫描仪(SEM)开展了持水曲线(SWRC)和微观结构的系列室内试验.研究结果表明,干湿循环的风化作用对原状和重塑黄土的持水性能有显著影响,且第一次循环的影响程度最为明显;原状黄土的 SWRC 呈双峰型,重塑黄土的SWRC呈单峰型;利用概念模型很好地解释了持水性的特征、变化规律及其与微观结构之间的联系.提出了一个考虑干湿循环次数、土的结构、区域差异影响的新持水模型,可以统一描述具有双峰特性的原状黄土和具有单峰特性的重塑黄土的持水特性,模型参数能够很好表达SWRC的变化特征,所提出模型在预测黄土和其他土的持水性能方面,具有较高的实用性和有效性.
Abstract
Wetting-drying cycles of weathering loading frequently lead to failure of infrastructures in loess regions,China.Water retention behaviours of loess are key information for capturing the physical causes of loess engineering problems.To demonstrate variations in water retention performance of intact and recompacted loess from three regions due to a purely environmentally driven deterioration process,laboratory testing programmes were carried out to measure soil water retention curve(SWRC)and microstructure,by incorporating employing a pressure plate apparatus and scanning electron microscope.According to the laboratory results,the wetting-drying weathering has a significant impact on the water retention properties of intact and recompacted loess,especially after the first wetting-drying cycle.A distinctive feature was that the SWRC of the intact loess was bimodal,whereas that of the recompacted loess was unimodal.The features of water retention behaviour and its variations as well as linking with soil microstructure were well interpreted by the conceptual model,considering multiple influences including wetting-drying cycles,soil fabric and regional variability.A new equation was proposed to provide a unified description about the water retentions of both intact loess with bimodal behaviour and recompacted loess with unimodal characteristics.The parameters were able to define the variables of SWRC,and it was highly usefulness and effectiveness in terms of external environmental influences,such as multiple wetting-drying cycles,soil fabric,regional differences and soil types.
关键词
黄土/持水性/风化作用/干湿循环/土结构Key words
loess/water retention behaviour/weathering loading/wetting-drying cycles/soil fabric引用本文复制引用
基金项目
National Natural Science Foundation of China(42027806)
National Natural Science Foundation of China(41907233)
出版年
2023
NETL
NSTL
维普
万方数据