ZHANG J, ZHAO H F, REN H C,et al.Experimental study on the strength and disintegration characteristics of carbonaceous slate in Qinchu Tunnel[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(4):131-139.

doi:10.16186/j.cnki.1673-9787.2024090011

Received:2024/09/05

Revised:2025/04/21

Published:2026/06/17

Experimental study on the strength and disintegration characteristics of carbonaceous slate in Qinchu Tunnel

Zhang Jian1, Zhao Haifeng1, Ren Huachun1, Peng Bo1, Liu Wei1, Zhang Huimei2, Fu Xiao2

1.Fourth Engineering Co.， Ltd.， China Railway 12th Bureau Group， Xi’an  710021， Shaanxi， China;2.School of Architecture and Civil Engineering， Xi'an University of Science and Technology， Xi’an  710054， Shaanxi， China

Abstract: Objectives During the tunnel construction， layered rock structures are prone to problems such as vault collapse and initial support cracking. Therefore， it is of great engineering value to deeply analyze the mechanical characteristics of layered rock.Carbonaceous slate， as a typical rock mass of layered metamorphic rock， exhibits poor interlayer cementation and is easily broken， which can lead to serious structural damage when tunneling through it， significantly reducing rock mass strength and altering its mechanical properties. This study aims to analyze the mechanical properties and clarify the disintegration mechanism of carbonaceous slate.  Methods Static disintegration tests， uniaxial compression tests and triaxial compression tests were carried out on carbonaceous slate. The mechanical properties of slate under different water content states and different bedding plane angles were analyzed， and the deformation failure modes and disintegration mechanisms of rock samples were discussed. Results The results show that： （1） The peak strength of dry samples is higher， the pre-peak stress-strain curve is approximately linear， and plastic failure occurs suddenly. The elastic modulus of the dry samples is higher than that of natural and saturated samples. After the peak strength， dry and natural samples exhibit different degrees of brittle drop， while the post-peak strength of the saturated samples （23.02 MPa） can still be maintained at approximately 21 MPa. （2） After multiple disintegration cycles， the disintegration degree of weakly weathered slate is low. For moderately weathered rock， water molecules entering the rock mass destroy cementation bonds and promote the formation of broken blocks， leading to disintegration. For fully weathered and strongly weathered slate， water absorption and swelling generate uneven stress， driving complete disintegration of the rock samples. Conclusions The research results can provide a reference for controlling large deformation and failure in soft rock tunnel construction under similar conditions.

Key words:tunnel engineering;carbonaceous slate;disintegration characteristics;mechanical properties