青藏铁路原状冻结砂土动力特性参数试验研究  

Experimental Study on Dynamic Characteristic Parameters of Undisturbed Frozen Sandy Soil of Qinghai-Tibet Railway

作　　者：何菲[1] 王旭[1] 刘德仁[1] 蒋代军[1] 刘博诗 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《铁道学报》2017年第6期112-117,共6页Journal of the China Railway Society

基　　金：国家自然科学基金(51268033);甘肃省青年科技基金(1606RJYA240)

摘　　要：以青藏铁路抗震研究为背景,研究原状冻结砂土动力特性参数。基于低温动三轴试验仪分析原状冻土动弹性模量、阻尼比及其与振动频率、围压和试验负温的关系。试验结果表明:动三轴试验温度-10^-0.6℃、围压0.1~0.5 MPa、荷载振动频率0.5~5Hz时,含水量为16.1%的青藏铁路DK1047+000段清水河原状冻结砂土动弹性模量试验值为900~1 350 MPa,阻尼比为0.04~0.15;随着荷载振动频率增大,冻土动弹性模量呈对数曲线增长;围压对冻土的作用分为增强效应和减强效应,围压较小时动弹性模量随着围压的增加而增大,达到临界围压后动弹性模量随着围压的增加而减小;动弹性模量随着温度降低线性增长,负温对动弹性模量影响较明显;频率、负温对阻尼比的影响与其分别对动弹性模量的影响呈近似相反的规律,随着围压的增加阻尼比分布变得分散。Based on the seismic research of Qinghai-Tibet Railway, the necessity of the research on the dynamic characteristic parameters of undisturbed frozen sand was proposed. Based on low temperature dynamic triaxial apparatus, the dynamic elastic modulus and damping ratio of undisturbed frozen soil and their relationship with vibration frequency, confining pressure and experiment negative temperature were analyzed. Test results showed that the experimental values of the dynamic elastic modulus of undisturbed frozen sandy soil in the DK1047＋000 section, with water content at 16.1-/00, of the Qinghai-Tibet Railway, were 900-1 350 MPa, and the damping ratio was 0.04-0.15, with the test temperature of the dynamic triaxial apparatus at --104 --0.6 -C, confining pressure at 0.1-0.5 MPa and load vibration frequency at 0.5-5 Hz. With the increase of the load vibration frequency, the dynamic elastic modulus of frozen soil increased logarithmically. The effect of confining pressure on frozen soil can be divided into enhancement effect and reduction effect： the dynamic elastic modulus increased with confining pressure when the confining pressure was relatively small. After the critical confining pressure was reached, the dynamic elastic modulus decreased with the increase of con fining pressure. Dynamic elastic modulus showed linear growth with the decrease of temperature, and the neg- ative temperature had the most significant influence on the dynamic elastic modulus. The influence of frequen- cy, and negative temperature on damping ratio was approximately contrary to the laws of their separate influence on dynamic elastic was more dispersed.

关 键 词：原状冻结砂土 动三轴试验 动弹性模量 阻尼比 温度 围压 

分 类 号：TU445[建筑科学—岩土工程]