Probabilistic evaluation of excavation unloading response of rock slope considering the uncertainty of mechanical parameters

Authors

Guo-feng LIU, School of Highway, Chang’an University, Xi’an, Shaanxi 710064, ChinaFollow
Kun FENG, School of Highway, Chang’an University, Xi’an, Shaanxi 710064, China
Chang-gen YAN, School of Highway, Chang’an University, Xi’an, Shaanxi 710064, ChinaFollow
Guang-liang FENG, State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
Ding-ping XU, State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
Chi ZHOU, School of Highway, Chang’an University, Xi’an, Shaanxi 710064, China

Abstract

There are many studies on the spatial variability of mechanical parameters of jointed rock masses and the reliability of slopes with potential slip surface, but the research on the spatial variability of mechanical parameters of rock slopes and the uncertainty analysis of excavation unloading response (deformation and plastic zone) is limited. A probabilistic evaluation method for excavation unloading response of rock slopes considering the uncertainty of mechanical parameters is proposed. Based on laboratory rock mechanical tests and geological survey mapping data, the probabilistic statistical models of rock mass mechanical parameters of slopes are constructed by using Hoek-Brown empirical criterion and Monte Carlo analysis method, in which the uniaxial compressive strength (UCS) of rocks, the geological strength index (GSI) and the parameters of rock mass joints are input, and these probabilistic models are checked by the chi-square test. Based on the point estimation principle, the combination scheme of rock mass mechanical parameters is constructed, and the simulation analysis of slope excavation process is carried out by the numerical method to obtain the probability distributions of the slope safety factor as well as the displacement and plastic zone of rock masses after excavation. This method is used to analyze the rock mass mechanical parameters and excavation unloading response of a cutting slope along the Beijing-Qinhuangdao expressway under construction. The values and uncertainty distributions of rock strength, elastic modulus, cohesion and internal friction angle are obtained. By using the point estimation and FLAC3D simulation method, the distributions of the slope safety factor as well as the displacement and plastic zone distributions of typical observation points are obtained. The comparison between the simulation results and the measured values shows the applicability of the proposed method. This study provides an effective way for the mechanical parameter estimation and stability evaluation of the rock cutting slope, and can provide a valuable reference for the decision-making process in practical engineering construction.

Graphic Abstract

Recommended Citation

LIU, Guo-feng; FENG, Kun; YAN, Chang-gen; FENG, Guang-liang; XU, Ding-ping; and ZHOU, Chi (2023) "Probabilistic evaluation of excavation unloading response of rock slope considering the uncertainty of mechanical parameters," Rock and Soil Mechanics: Vol. 44: Iss. 7, Article 6.
DOI: 10.16285/j.rsm.2022.6498
Available at: https://rocksoilmech.researchcommons.org/journal/vol44/iss7/6