**5. Summary**

This chapter presented observations showing that a jointed rock mass responds to temperature fluctuations. First, we presented a few examples of measurements observed at several monitoring stations around the world. The difficulty in field measurements is to isolate the effect of temperature from other environmental factors, such as water pressure in joints due to a freezing and thawing process. For this reason, Mount Masada is a preferred site for testing thermal mechanisms because of the prevailing desert conditions, where there is usually no pore pressure or freezing of underground water.

Then, a ratchet mechanism was used to explain how temperature changes can lead to cumulative displacement along a rock slope. Laboratory results of models of different sizes were presented, and the effect of the wedge size was demonstrated. Numerical analyses using 3DEC illustrate the effect of the wedge inside the tensile crack. We have seen that the wedge generally accelerates the cumulative response of the block system, and the maximum response occurs where the wedge length in about a third of the length of the sliding block.

The numerical analyses also make it possible to examine the contribution of daily and annual fluctuations. We saw that in the model of the block in Masada, the daily temperature fluctuations do not affect the block due to its large size. However, a sequence of several days with extreme temperatures for the season can lead to a cumulative response. Finally, based on the numerical analysis, rocks made of material with a high thermal expansion coefficient will respond more to the thermal mechanism.

### **Acknowledgements**

I thank Prof. Yossi Hazor for his support throughout the research. The laboratory work and the numerical analyses were carried out by Aviran Feldheim and Yuval Keissar, with the support of the Israel Science Foundation under contract no. ISF 1442/13. Christine Detournay from Itasca Consulting Group is thanked for her contribution.

## **Author details**

Dagan Bakun-Mazor Shamoon College of Engineering, Beer-Sheva, Israel

\*Address all correspondence to: daganba@sce.ac.il

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Rock Slope Stability under Temperature Fluctuations DOI: http://dx.doi.org/10.5772/intechopen.108464*
