摘要
随着寒区高等级道路工程等基础设施的建设,迫切需要对冻土压缩特性和静止土压力系数(K0系数)开展试验研究,但目前缺乏开展相关研究的专用仪器。本文基于融土侧限压缩试验的原理,结合冻土力学性质受温度控制的特性,自主研发了冻土侧限压缩试验仪。该仪器采用冷却罐内冷液循环和冷却罐外恒温箱实现二级控温,控温范围为-50℃至90℃,控温精度达±0.1℃;采用全数字伺服测控器实现温度闭环控制;采用高性能负荷框架结构,刚度大、重量轻,保证仪器在大荷载下平稳运行。利用该仪器对冻结饱和标准砂进行侧限压缩试验,试验结果验证了仪器可靠性。本仪器能准确快捷地测定冻土静止土压力系数和压缩性参数,是研究冻土力学特性并服务于寒区岩土工程建设的有力工具。
The compressibility of frozen soil should be considered in high-grade highway engineering and other infrastructure construction in permafrost regions.As an important parameter,the coefficient of lateral earth pressure at rest(i.e.,K0)for frozen soil and its changes with temperature need to be investigated.However,the related studies are inadequate so far because of a lack of the confined compression apparatus applicable to frozen soil.In order to accurately and quickly measure the above-mentioned mechanical properties of frozen soil,this paper developed a confined compression apparatus exclusively for frozen soil,which is in light of the experimental principle of the unfrozen soil compression and takes into account the characteristics of the mechanical properties of frozen soil which are dominated by temperature.In the new apparatus,the second-level temperature control is realized by adopting both a cold circulation in the cooling tank and a thermostat outside the cooling tank,which makes the control accuracy of temperature reach±0.1℃.Besides,the apparatus can achieve the closed-loop temperature control by using a full digital servo controller and can run smoothly under heavy loads by adopting a high-performance load framework with strong stiffness.The reliability of the apparatuses was verified through a series of confined compression tests on frozen standard sand.It was found that the self-developed apparatus can provide reliable compressibility parameters and K0 for practical engineering involving frozen soil materials.
作者
闫旭
孔令明
杨笑
姚晓亮
齐吉琳
YAN Xu;KONG Lingming;YANG Xiao;YAO Xiaoliang;QI Jilin(Beijing University of Civil Engineering and Architecture,Beijing 100044,China;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)
出处
《冰川冻土》
CSCD
北大核心
2019年第2期357-363,共7页
Journal of Glaciology and Geocryology
基金
国家自然科学基金面上项目(41572268)
北京市自然科学基金-市教委联合资助项目(KZ201810016020)资助.
关键词
冻土
仪器研制
侧限压缩
压缩性
K0系数
frozen soil
instrument development
confined compression
compressibility
K0 coefficient
