Damage Evolution and Circumferential Strain Distribution Characteristics of the Bolt-Supported Cavern under Multiple Explosion Sources

Taotao Wang,Weiliang Gao,Xiaowang Sun,Ansheng Cao,Guangyong Wang,Jianwei Cheng

doi:10.1155/2021/9985774

Abstract

The impact of multiple explosion sources on the safety of the underground cavern is enormous. Based on a similarity model test, the finite element software LS-DYNA3D was utilized to analyze the damage evolution and circumferential strain distribution characteristics of the bolt-supported cavern under the seven combinations of concentrated charge explosion sources in three places, including the side of the vault, side arch, and sidewall. The accuracy of the simulation results is verified by comparing them with test results. The research results indicate that the damage of the surrounding rock is mainly caused by the tensile stress wave reflected from the free surfaces and the superposition of the tensile stress wave. The damage of the surrounding rock in the cases of multiple explosion sources is not a simple superposition of that in the cases of a single explosion source. The peak circumferential stress and damage of the surrounding rock in the middle of two explosion sources are significantly greater than that of the cases of the corresponding single explosion source. In the seven cases, the peak circumferential strain of the cavern wall changes from tensile to compressive from the vault to the spandrel. When the explosion occurs on the sidewall, the peak circumferential strain of the floor is tensile.

Highlights

Underground engineering has been widely used in civil and military fields in recent years because of its advantages such as large storage space, little impact on the environment, and good concealment
Underground engineerings are vulnerable to explosions, such as blasting excavation and demolition, terrorist attacks by bombs, and there are usually multiple explosion sources when such explosions occur. e surrounding rock is disturbed during the explosion, and the stability of the underground cavern is significantly reduced [1]. erefore, it is of great practical significance to study the damage and strain distribution characteristics of underground caverns under multiple explosion sources
Zhu et al [2] studied the influence of internal explosions with different charge densities on the dynamic response and stress wave propagation of the surrounding rock caused by the explosion in the tunnel, and found that the charge density has a great influence on the dynamic response of the surrounding rock in an uncoupled underground explosion

Summary

Introduction

Underground engineering has been widely used in civil and military fields in recent years because of its advantages such as large storage space, little impact on the environment, and good concealment. Rough field tests, Xia et al [9] studied the influence of blasting excavation on the surrounding rock and lining system of the adjacent existing tunnel, and found that the damage degree of the surrounding rock increases linearly with the PPV. Using the geotechnical engineering anti-blast structure model [16], Gu et al [17,18,19,20] studied the antiblast performance of underground caverns with different charging and anchoring methods through similarity model tests. Many scholars [27,28,29] used numerical simulation methods to analyze the damage of underground caverns under the explosions by analyzing the PPV, displacement, and acceleration of the surrounding rock. Erefore, based on a similarity model test, the finite-element software LS-DYNA is used to build an underground cavern model that encounters multiple explosion sources.

Numerical Model

Results and Discussion

Conclusions