Stability Analysis of Surrounding Rock of an Underground Cavern Group and Excavation Scheme Optimization: Based on an Optimized DDARF Method

Abstract

The surrounding rock stability of an underground cavern group is an important issue in the process of cavern excavation, which has the characteristics of large displacement, discontinuity and uneven deformation, so the calculation and analysis are very complicated. The optimized discontinuous deformation analysis for rock failure method was adopted to analyze the stability of the surrounding rock of a real underground engineering cavern group under different excavation schemes. The cracking process of surrounding rock under different excavation schemes, the depth of crack expansion and the vertical displacement of the arch and bottom floor were obtained, and the following conclusions are drawn: (a) After the completion of the excavation, the stability problems mainly appeared in the surrounding rocks of the arch, left wall, right wall and bottom floor of the main powerhouse, in the surrounding rocks of the arch, left wall and bottom floor of the main transformer chamber and in the surrounding rocks of the arch, right wall and bottom floor of the tailrace surge tank. (b) Fault f2 has an influence on the stability of the surrounding rock of the tailrace surge tank, while fault f1 has no influence on the stability of the cave group. (c) The scheme of simultaneous excavation of three caverns shows the advantages in the crack propagation depth of surrounding rock and vertical displacements of caverns.

Study on the Impact of Different Parameters on Prediction of Crown Deformations in Underground Caverns

“…The surrounding rock stability of an underground cavern group is an essential issue in the process of cavern excavation, which has the characteristics of large displacement, discontinuity, and uneven deformation, making computation and analysis difficult. By observing the destruction process of a jointed rock mass, the discontinuous deformation analysis for the rock failure approach was used to analyze the stability of the surrounding rock [13]. A support vector machine (SVM) is used to forecast the allowed deformation of surrounding rock.…”

“…Three parameters are considered: rock mass categorization, cavern buried depth, and cavern size. The mapping association between permitted deformation and the three influencing factors described above is established [13].…”

An Analysis of Two Case Studies on the Construction of Underground Caverns-A Focus on the Tiantai Pumped Storage Station

“…[5] Ma H et al (2023) have considered three factors that affect the stability of surrounding rock: excavation sequence, excavation method and support measures. [6] Hu et al (2022) have applied a method of back analysis to be utilized for the interpretation of field measurements in monitoring the stability of tunnels. [7] However, these researchers have not considered the beam crane and rock support during construction, and these problems have been addressed in this paper.…”

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.…”