*Article* **A Calculation Method of Thermal Pore Water Pressure Considering Overconsolidation Effect for Saturated Clay**

**Gailei Tian and Zhihong Zhang \***

Key Laboratory of Urban Security and Disaster Engineering of China Ministry of Education, Beijing University of Technology, Beijing 100124, China; tiangailei@emails.bjut.edu.cn **\*** Correspondence: zhangzh2002@bjut.edu.cn

**Abstract:** With the increase of soil consolidation degree, the pore water pressure induced by thermal loading drops dramatically. To conveniently and quickly calculate the thermal pore water pressure inside the soil under different overconsolidation states and quantify overconsolidation effect on thermal pore water pressure, a calculation method of thermal pore water pressure considering overconsolidation effect for saturated clay is proposed. The method is verified by the relevant experimental data, and good agreements were achieved. Through analyzing the influence mechanism of *OCR* on the thermal pore water pressure, three important findings were captured. (1) For overconsolidated clay, thermal pore water pressure decreases nonlinearly with the increase of *OCR*. (2) There is a critical threshold of *OCR* 4.3; when 1 < *OCR* ≤ 4.3 (slightly overconsolidated state), the ratio of compression line slope to recompression line slope (*Λ*) of overconsolidated clay is consistent with that of the normally consolidated clay, while when *OCR* > 4.3 (highly overconsolidated state), the value of *Λ* is smaller than that of normally consolidated clay. (3) For highly overconsolidated clay (*OCR* > 4.3), considering the reducing of *Λ* with *OCR*, the prediction accuracy of the thermal pore pressure calculation method has been greatly improved; especially when *OCR* equals 30, the prediction accuracy improves by 92.7% as temperature change achieves 35 ◦C.

**Keywords:** overconsolidation effect; thermal pore water pressure; calculation method; saturated clay
