基于里氏硬度计无损测量方法评价石质文物的风化程度

里氏硬度计因具有冲击能量小、对冲击方向要求不严格、对岩石的强度变化比较敏感等特点，使其可以应用于岩石的无损测量中。利用该仪器对山西大同云冈石窟片状风化岩面进行了测量，现场3个测量区域的平均里氏硬度值分别为224.8、225.8和236.4。而相同岩性的新鲜岩芯的平均里氏硬度值为661.4。根据上述测值，定义了风化程度，即风化岩石的里氏硬度值与新鲜岩石的里氏硬度值之比。据此，得到现场3个测量区域的风化程度分别为：0.34、0.34、0.36。根据文献总结的里氏硬度值与单轴抗压强度之间的公式，得出了上述3个测量区域的单轴抗压强度分别为6.06 MPa、6.13MPa、6.87MPa。

ESTIMATING THE WEATHERING DEGREE OF ROCK SURFACE OF CULTURAL RELIC FROM LEEB HARDNESS FOR NON-DESTRUCTIVE MEASUREMENT

Equotip(Leeb hardness tester) is invented by Dietmai Leeb in the 1970s. At first, it was designed for detecting the hardness of metal materials. For it has the characteristics of small impact energy, undemanding impact direction, more sensitive to rock strength changes, it can be applied to non-destructive measurement of rocks. The authors used it to measure flake weathered rock surface of Yungang Grottoes, Datong, Shanxi province. The average hardness values of three chosen measurement regions were 224.8, 225.8 and 236.4,respectively. However, the average Leeb hardness value of unweathered rock with the same lithology was 661.4. According to the above measured values, the authors define the weathering degree, that is the ratio of the hardness values of weathered rock to that of fresh rock. Accordingly, the weathering degrees of the three measurement regions were 0.34, 0.34 and 0.36 respectively. According to the formula of Leeb hardness value and uniaxial compressive strength summarized in the literature, it also obtained that the uniaxial compressive strength of the three measurement regions were 6.06MPa, 6.13MPa and 6.87MPa, respectively.