A New Empirical Approach to Estimate the Ratio of Horizontal to Vertical in-Situ Stress and Evaluation of Its Effect on the Stability Analysis of Underground Spaces

Abstract

In-situ stress is one of the most important input data to study stability analysis of underground and surface geomechanical projects. The measured vertical stress has a linear relation with depth. The average value of unit weight (g) was obtained 0.026 MN/m3 (2.56 ton/m3) using 1041 test results of different rocks with 0.001 difference with 0.027 MN/m3 which is a reliable coefficient for estimating vertical stress. The ratio of horizontal (sh) to vertical (sv) stress (K =sh/sv) is estimated by theoretical and empirical methods. The results showed that the estimating ratio of horizontal to vertical stress (K) by a theoretical method such as Terzaghi and Richard is much smaller than 1, and the estimation of the K value utilizing empirical methods such as Hoek and Brady is much greater than 1, with its value even approaching 4 in the near ground surface. To overcome the lack of an applicable comprehensive relation for the estimation of the K ratio and improve the shortcomings of previous methods, a new empirical relation was developed to estimate the K ratio utilizing a significant number of in-situ test results. Stability analysis of Masjed Soleyman powerhouse caverns was carried out by numerical modelling for five values of the K ratio obtained by previous stress estimation methods and this study. The in-situ stress estimation method (K ratio changes) showed a significant effect on stresses, displacements, strains, depth of the plastic zone and significantly affect the stability analysis and support system design of the powerhouse and transformer caverns.

Characteristics of Perimeter Rock Damage in a Bottom-Pumping Roadway under the Influence of Mining Activities and Rational Location Studies: A Case Study

“…With the gradual expansion of deep mining for coal resources in China, coal and gas outbursts in mines have become more and more serious. To ensure safe production in mines, it is extremely important to arrange the bottom pumping roadway on the floor of the working face for gas drainage from the upper working face [1][2][3][4][5]. However, when the working face is being mined back, the bottom plate is affected by the mining of the working face, and the stress is transferred to the deep part of the bottom plate of the working face of the roadway, which redistributes the stress in the rock surrounding the bottom plate.…”

Back Analysis and Stability Prediction of Surrounding Rock During Excavation of the Shuangjiangkou Underground Powerhouse

“…The underground caverns of the hydropower station are usually located in a complex geological environment. The stability of these caverns is affected by various factors, such as mechanical properties of surrounding rock (He et al, 2021;Sudhakar et al, 2023;Sun et al, 2023), insitu stress (Moomivand et al, 2022;Sainoki et al, 2020;Zhang et al, 2021), unfavorable geological structure (Kuili & Sastry, 2023;Ma et al, 2020a;Prajapati & Verma, 2023), underground water (Li et al, 2014;Xu et al, 2020), and excavation method (Chandra et al, 2010;Ma et al, 2023;Rahimi et al, 2021). Due to the uncertainty of geological conditions, it is not easy to obtain all details of geological and environmental factors.…”

Springs of Variable Stiffness in the Control of Seismic Actions in Buildings

“…Contributing to this event is the existing stress on the geomechanics surface (Moomivand et al, 2022). Particularly, in their study, Preve et al (2017) state that the tremors that happen in Brazil have occurred mainly due to neotectonic failures.…”