在放射性核废料处置、地热能源开采以及地下油气储存等工程中，热量的传递将会在很大程度上改变岩土材料的力学性质，因此，岩土体及缓冲材料的热力学参数，包括热传导系数、热膨胀系数、比热容对工程设计以及安全性评价有着至关重要的作用。利用自主研制的岩石膨胀系数测试仪对含层理砂岩进行了热膨胀系数试验，研究了岩石轴向和径向热膨胀系数的变化规律，结果表明：对于含水平层理岩样，随着温度的变化，当膨胀均匀后，轴向热膨胀系数约为14×10-6 ℃-1，而径向热膨胀系数约为9×10-6 ℃-1，前者约为后者的1.56倍，表现出明显的各向异性；相比于含水平层理岩样，含竖直或倾斜层理岩样的轴向膨胀系数未见显著差异，但径向热膨胀系数明显增加；相同温度下，径向热膨胀系数从大到小的顺序为：竖直方向、倾斜方向和水平方向；由于岩样中沉积层的存在，砂岩与沉积物质的膨胀性能并不相同，这将导致岩样的轴向和径向热膨胀系数表现出各向异性。该研究成果对于岩体的热-力耦合特性研究具有一定的参考意义。

Heat transportation will change the mechanical properties of rock and soil materials considerably in subsurface engineering applications such as radioactive waste repositories, geothermal energy extraction and underground oil/gas storage. Thermal properties of rocks, soils and buffer materials, including thermal conductivity, thermal expansion coefficient, specific heat capacity, play a crucial role in design and evaluation of safety performance of these projects. The thermal expansion coefficient tests are conducted on sandstone with bedding planes by using the independently developed instrument for thermal expansion coefficient of rocks. The evolution of axial and radial thermal expansion coefficients of rocks are studied. The results show that for rock samples with horizontal beddings, with the change of temperature, axial thermal expansion coefficient is about 14×10?6 ℃?1, while about 9×10?6 ℃?1 in radial direction under uniform expansion. The axial thermal expansion coefficient is about 1.56 times as large as the radial thermal expansion coefficient, and the rock sample shows obvious anisotropy. Compared with rock samples with horizontal beddings, the samples with inclined and vertical beddings shows no significant difference in axial thermal expansion coefficient, but their radial thermal expansion coefficients are larger. Under the same temperature, the order of radial expansion coefficient from big to small is vertical, inclined and horizontal beddings. Because of the existence of beddings, the expansion properties of sandstone and compositions of beddings are different, which leads to the difference of axial and radial expansion coefficients. The results may provide a helpful reference for better understanding the thermo-mechanical behaviors of rocks.