循环荷载下风积沙填料的临界动应力  

Critical Dynamic Stress of Wind⁃blown Sand Filler Under Cyclic Load

作　　者：胡国星 HU Guoxing(China Railway Urumqi Bureau Group Co.Ltd.,Urumqi 830011,China)

机构地区：[1]中国铁路乌鲁木齐局集团有限公司,乌鲁木齐830011

出　　处：《铁道建筑》2023年第8期113-118,共6页Railway Engineering

基　　金：中国铁路乌鲁木齐局集团有限公司科技研究开发计划课题(WLMQ-KGHZGS-HRTL-GGB-2020-0032)。

摘　　要：针对我国沙漠铁路中风积沙填料在列车动荷载作用下动力性能不明确的问题,研究风积沙填料在列车循环荷载作用下的变形特性,考虑动应力幅值、含水率和围压的影响进行了风积沙填料动三轴试验;分析了风积沙试样累积塑性变形的发展规律,建立了风积沙塑性变形行为判定标准,获得了风积沙填料的临界动应力。结果表明:风积沙试样的累积塑性应变与循环振次的关系曲线可划分为稳定型、临界型和破坏型三种类型;风积沙累积塑性应变速率与循环振次呈幂函数关系,得出了风积沙填料塑性行为判定标准;以安定准则为破坏判据,在风积沙填料塑性行为划分基础上,引入静强度参数反映土体自身物理性质对动应力水平的影响,得到了考虑动应力幅值、含水率及围压的风积沙填料临界动应力经验公式。In response to the issue of unclear dynamic performance of wind-blown sand fillers on desert railways in China under train dynamic loads,the deformation characteristics of wind-blown sand fillers under train cyclic loads were studied to obtain the critical dynamic stress of wind-blown sand fillers.Dynamic triaxial tests of wind-blown sand fillers were conducted considering the effects of dynamic stress amplitude,moisture content,and confining pressure.The development law of cumulative plastic deformation of wind-blown sand samples was analyzed,and the criteria for determining the plastic deformation behavior of wind-blown sand were established.The critical dynamic stress of the wind-blown sand filler was obtained.The results show that the relationship curve between cumulative plastic strain and cyclic vibration frequency of wind-blown sand samples can be divided into three types,namely stable type,critical type,and failure type.The cumulative plastic strain rate of wind-blown sand is a power function relationship with the cyclic vibration frequency,and the criteria for determining the plastic behavior of wind-blown sand fillers are obtained.Taking the stability criterion as the failure criterion,based on the division of plastic behavior of wind-blown sand fillers,the static strength parameter is introduced to reflect the influence of the physical properties of the soil on the dynamic stress level.An empirical formula for the critical dynamic stress of wind-blown sand fillers considering the amplitude of dynamic stress,water content,and confining pressure is obtained.

关 键 词：沙漠铁路 路基填料 风积沙 动三轴试验 临界动应力 循环动荷载 

分 类 号：TU431[建筑科学—岩土工程]