冻土抗侵彻试验靶体制备及其冻结温度场模拟研究

Preparation of target for frozen soil anti-penetration test and numerical simulation of frozen temperature field

不同赋存温度环境下的各类型冻土材料热物理特性存在显著差异,开展高寒高海拔地区多年冻土抗侵彻特性研究时,能制备出满足温度控制要求的冻土靶体并揭示出靶体内冻结温度场的分布规律是后续开展大量侵彻模型试验最为基础而重要的工作。通过研究不同温度下温度场和水分场中热物理参数对冻土靶体制备的耦合影响,获取模型试验所需冻土靶体内部温度梯度分布规律,确定试验靶体达到设定温度时所需要的时间,阐述冻土抗侵彻试验靶体制备技术并对冻结粘土、冻结砂土、冻结粉土等3种典型冻土抗侵彻靶体的温度场进行了数值模拟。研究表明在同等条件下,粉土靶内部温度梯度达到一致所需要的时间最长,粘土靶次之,而砂土靶所需要的时间最短,为后续顺利开展冻土抗侵彻特性模型试验提供依据。

There are significant differences in thermal physics of frozen soil under different storage temperatures.Before analysing anti-penetration properties of permafrost in high-cold and high-altitude permafrost areas,it is the most basic and important work to prepare frozen soil target that meets the temperature control requirements as well as revealing the distribution law of temperature fields.By studying the coupling influence of thermophysical parameters on the preparation of frozen soil targets at different temperatures,obtain the internal temperature gradient distribution law of the frozen target required for the model test,and determine the time required for the test target to reach the set temperature.The target preparation technology of frozen soil anti-penetration test is expounded and the numerical simulation of the temperature fields of three typical frozen soil anti-penetration targets,including frozen clay,frozen sand,and frozen silt,is carried out.The study shows that under the same conditions,the time required for the temperature gradient inside the silt target to reach consistency is the longest,followed by the clay target,and sand target requires the shortest time,which provides a basis for the subsequent test.