贺兰口岩石作为宁夏的文物载体,中国,已经遭受了由变化的环境条件引起的严重风化。为研究贺兰口遗迹载体岩的冻融破坏特征,三种干湿条件(即,干燥,pH=2和pH=7)以及冻融实验已在0、10、20、30和40个循环中进行。此外,在4MPa的四个不同的电池压力下进行了一系列三轴压缩试验,8MPa,16MPa,和32MPa,与无损声发射技术配合使用。随后,根据弹性模量和声发射振铃计数确定岩石损伤变量。已经发现,声发射定位点反映了在较高的单元压力下,裂纹将集中在主裂缝表面附近。值得注意的是,0次冻融循环的岩石样品在纯剪切下失效。然而,在20次冻融循环中观察到剪切滑移和沿拉伸裂纹的延伸,而拉伸-斜剪切破坏发生在40次冻融循环。毫不奇怪,观察到岩石内部劣化的降序为(干燥组)>(pH=7组)>(pH=2组)。还发现这三组中损伤变量的峰值与冻融循环下观察到的恶化趋势一致。最后,半经验损伤模型可以严格确定岩石样品的应力和变形行为,从而为贺兰口遗址保护框架的建立提供理论依据。
The Helankou rock as the relics carrier in Ningxia, China, have been suffering from serious weathering caused by variable environmental conditions. To study the freeze-thaw damage characteristics of Helankou relics carrier rocks, three dry-wet conditions (i.e., drying, pH = 2 and pH = 7) together with freeze-thaw experiments have been carried out at 0, 10, 20, 30, and 40 cycles. Additionally, a series of triaxial compression tests have been carried out at four different cell pressures of 4 MPa, 8 MPa, 16 MPa, and 32 MPa in tandem with a non-destructive acoustic emission technique. Subsequently, the rock damage variables were identified based on elastic modulus and acoustic emission ringing counts. It has been revealed that the acoustic emission positioning points reflected that the cracks would be concentrated near the surface of main fracture at higher cell pressures. Notably, the rock samples at 0 freeze-thaw cycles failed in pure shear. However, both shear slip and extension along the tensile cracks were observed at 20 freeze-thaw cycles, while tensile-oblique shear failure occurred at 40 freeze-thaw cycles. Not surprisingly, the decreasing order of deterioration inside the rock was observed to be (drying group) > (pH = 7 group) > (pH = 2 group). The peak values of damage variables in these three groups were also found to be consistent with the deterioration trend observed under freeze-thaw cycles. Finally, the semi-empirical damage model could rigorously ascertain stress and deformation behavior of rock samples, thus providing theoretical basis to establish a protection framework for Helankou relics.