大型多功能冻土-结构接触面循环直剪系统研制及应用

在天然冻土区和人工冻土工程中存在着大量冻土与结构物接触面问题，而目前尚无有关此类接触面剪切行为的试验研究手段。为此，研制了大型多功能冻土-结构接触面循环直剪系统DDJ—1，该系统性能优异：能实现0～-20℃范围内对接触面温度的精确控制；能精确施加常刚度、常位移、零法向应力和常应力4种法向边界条件；能够模拟多种粗糙度的接触面实现循环和单调两种剪切形式；能够观测接触带的破坏状态和厚度，同时可以测量接触带土体内部的剪切位移；应力施加、位移控制和温度调节精准。试验结果表明：该系统能准确地再现冻土与结构接触面的力学行为、变形行为，可为系统开展冻土-结构接触面的研究提供试验基础和重要思路。

Development and application of large-scale multi-functional frozen soil-structure interface cycle-shearing system

In the permafrost regions and artificial frozen soil projects, there are many problems of interface between frozen soils and architectural construction, but there is no related test equipment, which can be used for researches on frozen soil-structure interface. Based on this, a new apparatus called large-scale multi-functional cycle direct shear apparatus for frozen soil-structure interface (DDJ — 1) is developed. The shear system is excellent in many performances: (1) the system can precisely realize the temperature control in the range of 0～-20℃; (2) four normal boundary conditions, including constant stress, constant displacement, constant stiffness and zero stress, can be exerted accurately in the system; (3) various roughnesses of interface can be simulated; (4) two shear forms, circular shear and drab shear, can be provided; (5) the state of failure, thickness and shear displacement of the shear bands in frozen soils can be monitored; and (6) the stress applying, displacement control and temperature regulation can be precisely measured. The test results show that the apparatus can accurately reproduce the mechanical and deformational behaviors of the interface between frozen soils and structures, meanwhile, it can provide a experimental basis and important ideas for carrying out researches on the frozen soil-structure interface.