Mechanical Properties and In-situ Stress Measurement by Rock Core Samples Drilling from a Large Section Underground Station

Abstract Chongqing is a mountain city in western China, with complex geological environment, which brings many difficulties to the construction of large section underground projects. The construction experience of a large number of underground projects shows that ordinary engineering geological survey is difficult to meet the requirement of engineering design and construction. Therefore, on the basis of the initial survey, intensive drilling and coring work were carried out for the engineering area of the Guobo underground station with large cross-section to be built, and the basic mechanical, softening properties of the surrounding rock and in-situ stress field of the project area are obtained by laboratory tests. Based on the present experimental results and engineering experiences, it is proposed that the potential risks of Guobo station excavation include: ①bias pressure;②High in-situ stress;③Surrounding rock deterioration. The present study has practical significance for the design and construction of Guobo underground station, and it has certain reference value for the construction of underground projects in similar geological areas.