中文摘要：

为测试岩土体在冻融过程中温度场、冻胀力、冻融变形等物理量随温度的变化过程,研制了具有加载、冷量控制、温度场测试、三维应力测试和三维应变测试等多种功能的冻土模型试验系统。该试验系统由模型箱、加载系统、冷冻系统、温度测试系统、三维冻胀力测试系统、三维冻胀变形测试系统等部分组成。模型箱由大尺寸槽钢通过螺栓连接而成,可保证内置土体在冻胀时箱体不发生变形。加载设备由6个300 kN千斤顶组成,可对土体施加竖向荷载。冷冻系统由冷冻机、冻结器及连接管路组成,可调节出口冷媒温度和冷媒流量。温度测试系统由23个温度传感器组成,可测试箱体内任意时刻任意位置处土体的温度。自制的三维冻胀力测试装置由位于不同方向上的6个高精度土压力盒组成,能测试岩土体在冻融过程中一点的三维应力状态。自制的三维应变测试装置由位于不同方向上的12个应变片组成,能测试土在冻融过程中一点的三维应变状态。针对天津地铁5号线某联络通道冻结法施工遭遇粉土的模型试验表明：该试验系统具有组装灵活、操作简单、性能稳定可靠、测试参数全面准确等特点。

英文摘要：

In order to investigate the changes of temperature,stress and strain field in freezing or thawing process of soil,a model test system was developed which could apply load, control refrigerating capacity, and measure temperature,three-dimensional stress and three-dimensional strain in the model room. The model test system consisted of model room,loading system,freezing system,temperature measurement system,three-dimensional stress and strain measurement system,etc. The model room was constructed by large channel steel with bolts to ensure rigidity. The loading set-up consisted of six 300 kN jacks which could apply vertical load on the soil. The freezing system consisted of a refrigerating machine,freezer and connecting pipe,by which temperature and flow of refrigerant were adjustable. The temperature measurement system consisted of a total of 23 temperature sensors could be used to read soil＇s temperature at any time. In order to test three-dimensional stress at a point during freezing and thawing process,a self-designed three-dimensional stress set-up consisted of six high-precision earth pressure cells and a base was located in different directions. A three-dimensional strain measuring set-up was made by 12 routine strain gauges to detect overall strain condition during freezing or thawing process. The frozen progress and corresponding measurement on silt which was taken from Tianjin Metro Line 5 connectional passage showed that the model test system had the advantages of flexible assembly,easy operation,stable performance,and comprehensive and accurate test parameters.