Study on Brazilian splitting test of bedding limestone slope deformation failure

Abstract

The slope along north section of the Beijing–Zhuhai expressway in Guangdong province is mainly limestone bedding slope. To reveal the relationship between the deformation failure modes of limestone slopes and the bedding angle of the strata, a targeted experimental research and theoretical analysis has been carried out, which provides a basis for the stability criterion of bedding limestone slope. In this paper, the slope samples along the expressway are selected and grouped according to different layer angle θ, and the Brazilian disc splitting test has been carried out. According to the experiment, it is found that with the change of limestone bedding angle, five failure modes would occur: ① When the bedding angle is between 0° and 30°, pure tensile failure occurs. ② 30°–45°, tensile-slip type failure. ③ 45°–75°, the slip-crack type failure. ④ 75°–90°, the slip type failure. ⑤ θ = 90°, the compression type failure. And the tensile strength of the limestone decreases as the bedding angle θ changes from 0° to 90°. Secondly, the criterion of bedding limestone slope’s overall slip failure and the partial slip-crack failure is deduced. The critical slope height equation of overall slip failure and the critical slope length equation of partial slip-crack failure are obtained. Finally, we have taken an application in a limestone slope which located in Guangdong Province Beijing–Zhuhai expressway north section. The theory agrees well with the actual stability of bedding limestone slope.