ZHAN 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), doi:10.16186/j.cnki.1673-9787.2024090011.

doi: 10.16186/j.cnki.1673-9787.2024090011

Received：2024-09-05

Revised：2025-04-21

Online：2025-05-14

Experimental study on the strength and disintegration characteristics of carbonaceous SLATE in Qinchu tunnel(Online)

ZHANG Jian¹, ZHAO Haifeng¹, REN Huachun¹, PENG Bo¹, LIU Wei¹, ZHANG Huimei², FU Xiao²

(1. China Railway 12th Bureau Group Fourth Engineering Co., Ltd., Xi'an 307100, Shaanxi; 2 School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.)

Abstract: During the construction of the tunnel, because the layered rock structure is easy to cause problems such as vault collapse and initial support cracking, it is of great engineering practical value to deeply analyze the mechanical characteristics of layered rock. As a typical rock mass in layered metamorphic rock, carbonaceous slate has poor interlayer cementation and is easy to break, which will lead to serious structural damage when tunneling through carbonaceous slate. The strength of rock mass decreases greatly and the mechanical properties change. Objectives In order to analyze the mechanical properties of carbonaceous slate and clarify the disintegration mechanism of carbonaceous slate. Methods In this paper, the static disintegration test, uniaxial compression test and triaxial compression test were carried out with carbonaceous slate as the research object. The mechanical properties of slate under different water contents and different bedding angles were analyzed, and the deformation failure mode and disintegration mechanism of rock samples were discussed. Results The results show that : (1) The peak strength of the sample in the dry state is higher, the change trend of the curve before the peak is approximately linear, the plastic failure is sudden, and the elastic modulus of the dry sample is higher than that of the natural and saturated conditions. After the peak strength, the sample (dry, natural) showed different degrees of brittle drop phenomenon, while the peak strength of the saturated sample (23.02MPa) can still be maintained (about 21MPa) ; (2) After multiple disintegration cycles, the disintegration degree of weakly weathered slate is low, and the reason for the disintegration of moderately weathered rock is that water molecules enter the rock mass to cause the destruction of cementation bonds and promote the formation of broken blocks. The water absorption and expansion of fully weathered and strongly weathered slate at the same time produce uneven stress to promote the complete disintegration of rock samples. Conclusions The research results can provide a research basis for the control of large deformation and failure of soft rock tunnel construction under similar conditions.

Key words: Tunnel engineering; Carbonaceous SLATE; Disintegrability; Mechanical property