Impact compression properties of artificial cemented sand material under active confining pressure

Ying Xu,Jinjin Ge

doi:10.21595/jve.2020.20897

Abstract

In order to explore the mechanical properties of rock with deep in-situ stress under explosive impact, cemented sand material (artificial material) instead of rock was used to carry out impact dynamics test under the condition of confining pressure. The experimental results show that the stress-strain curve of cemented sand specimens tested by triaxial impact compression changes significantly compared with those tested by uniaxial impact compression. The dynamic failure mode of cemented sand specimens placed under confining pressure constraints is one of axial tensile failure, while the dynamic compressive growth factor, peak strain, dynamic elastic modulus, and specific energy absorption of cemented sand specimens all have the characteristics correlated with confining pressure. The research results in this study can be as an important basis for the mechanism analysis of rock breaking by blasting in deep rock mass.

Highlights

The mining of deep-underground resources has become a normal state [1], in which the mining depth of coal has reached 1500 m, the mining depth of geothermal resources has exceeded 3000 m, the mining depth of non-ferrous metal mines has exceeded 4350 m, and the mining depth of oil and gas resources has reached 7500 m [2].When blasting is carried out at a depth of kilometers or even thousands of meters, the fracture of the rock shows different characteristics from that of the shallow rock
This study focuses on the dynamic mechanical properties of deep rock mass subjected to impact by explosion
According to uniaxial and triaxial impact compression tests on cemented sand specimens, it is found that confining pressure has a great influence on its dynamic compression performance, mainly including: 1) The dynamic compression deformation and failure of the specimen under confining pressure has only elastic stage, yield stage and failure stage, which reduces the compaction stage compared with that under unconfining pressure

Summary

Introduction

The mining of deep-underground resources has become a normal state [1], in which the mining depth of coal has reached 1500 m, the mining depth of geothermal resources has exceeded 3000 m, the mining depth of non-ferrous metal mines has exceeded 4350 m, and the mining depth of oil and gas resources has reached 7500 m [2].When blasting is carried out at a depth of kilometers or even thousands of meters, the fracture of the rock shows different characteristics from that of the shallow rock. The confining pressure value commonly used in laboratories to characterize the high in-situ stress state of rock at present is only a dozen MPa, which is not consistent with the high in-situ stress state of deep rock mass. Solutions to these problems mainly focus on improving test instruments, increasing the impact velocity of bullets, or seeking alternative similar materials, which can simulate high in-situ stress and large explosive load with low confining pressure and impact velocity. Using similar materials instead of rocks, which can be used in dynamic impact test, is the most economical and practical method

Methods

Results

Conclusion