A Numerical Study of Underground Cavern Stability by Geostress Characteristics

The stability of underground cavities is of increasing importance considering the predominant cavity locations built up in high mountain and canyon environments. Such cavity locations are characterized by a high initial in situ stress, which results in brittle fracture and deformation of the surrounding rock during cavity construction. This paper presents a numerical study of underground cavern stability considering four factors, namely, mechanical property of surrounding rock, cavern burial depth, lateral pressure coefficient in horizontal direction, and the angle included between plant longitudinal axis and horizontal principal stress. Analytical methods including the key point displacement in side wall, plastic zone volume, and splitting fracture volume are used to characterize the stability of underground cavern. A modified formula to predict side wall displacement is proposed based on prior work, which is applicable to 3D computation model by taking horizontal geostress in two directions into account. Eventually, the optimal layout of underground cavern is put forward under different conditions of geostress field.