Particle Size Distribution Effects on the Strength Characteristic of Cemented Paste Backfill

Jiangyu Wu,Meimei Feng,Xianbiao Mao,Yiming Wang,Zhanqing Chen,Guansheng Han

doi:10.3390/min8080322

Abstract

It is of great significance, for economic, environmental and security reasons, to investigate the strength characteristic of underground cemented paste backfill (CPB). Consequently, an ultrasonic test, uniaxial and triaxial compression experiment, and acoustic emission (AE) monitoring were carried out on CPB, for which the particles satisfied Talbot gradation. The homogeneity of CPB specimens was evaluated by ultrasonic pulse velocity (UPV). The stress–strain behavior and AE characteristic of CPB specimens under different Talbot indices and confining pressures were investigated. The effects of the particle size distribution and the confining pressure on the peak strength of CPB were analyzed. The strength parameter model of CPB under the coupled influence of the particle size distribution and the confining pressure was constructed based on the Mohr–Coulomb strength criterion. The results show that the peak strength of CPB is positively linear with confining pressure, however, the relationship between its strength parameters and the Talbot index can be characterized by a quadratic polynomial function. This suggests that there is an optimal gradation of particles reflected in the maximum strength of CPB.

Highlights

Cemented paste backfill (CPB) is a relatively new green material, composed of waste rocks and cementing materials with water, widely used in green mining [1,2,3]
The stress–strain behavior and acoustic emission (AE) characteristic of cemented paste backfill (CPB) specimens under different Talbot indices and confining pressures were investigated
The strength parameter model of CPB under the coupled influence of the particle size distribution and the confining pressure was constructed based on the Mohr–Coulomb strength criterion

Summary

Introduction

Cemented paste backfill (CPB) is a relatively new green material, composed of waste rocks and cementing materials with water, widely used in green mining [1,2,3]. The backfill must maintain its mechanical stability, so investigating its strength characteristic under compression is of significant interest [8,9,10] For this purpose, lots of studies have focused on the strength characteristic of CPB, mostly from the perspective of the differences in cementing materials such as the type and content [11,12,13], additives such as nano-material, polymer, fiber, alkaline substances, and water-absorbing substances [14,15,16,17,18,19,20], and environmental conditions such as temperature, corrosion and conservation [21,22,23,24,25,26,27]

Methods

Results

Conclusion