Results 21 to 30 of about 5,494,240 (282)

Unloading responses of pre-flawed rock specimens under different unloading rates

Transactions of Nonferrous Metals Society of China, 2019
Abstract Based on the stress redistribution analysis of rock mass during the deep underground excavation, the unloading process of pre-flawed rock material was simulated by distinct element method (DEM). The effects of unloading rate and flaw inclination angle on unloading strengths and cracking properties of pre-flawed rock specimens are numerically
Xibing Li, Lei Weng
exaly   +2 more sources

Mechanical Characteristics of Frozen Sandstone under Lateral Unloading: An Experimental Study

Advances in Civil Engineering, 2021
The lateral unloading strength and deformation of surrounding frozen rock are the key parameters for safety evaluation of frozen shaft construction. A low-temperature and high-pressure rock triaxial test system was used to simulate freezing construction,
Shuai Liu, Gengshe Yang, Xihao Dong, Yanjun Shen, Hui Liu   +4 more
doaj   +2 more sources

Excavation unloading‐induced fracturing of hard rock containing different shapes of central holes affected by unloading rates and in situ stresses [PDF]

Energy Science & Engineering, 2020
Slabbing failure and strain rock burst are the main failure patterns during the excavation and construction phases of deep tunnels in hard and brittle rock, which cause unexpected equipment damage and casualties.
Fan Feng, Shaojie Chen, Diyuan Li, Wanpeng Huang, Kang Peng, Chuanwei Zang   +5 more
doaj   +2 more sources

Deformation and damage properties of rock-like materials subjected to multi-level loading-unloading cycles [PDF]

Journal of Rock Mechanics and Geotechnical Engineering, 2023
In the process of engineering construction such as tunnels and slopes, rock mass is frequently subjected to multiple levels of loading and unloading, while previous research ignores the impact of unloading rate on the stability of rock mass.
Zhizhen Liu, Ping Cao, Qingxiong Zhao, Rihong Cao, Fei Wang   +4 more
doaj   +2 more sources

Experimental Investigation of Unloading-Induced Red Sandstone Failure: Insight into Spalling Mechanism and Strength-Weakening Effect

Advances in Civil Engineering, 2020
To study the effect of excavation unloading on hard rock failure, a series of true-triaxial compression tests, biaxial compression tests, and true-triaxial unloading compression tests (two different unloading rates) at different confining pressures was ...
Yong Luo, Fengqiang Gong, Dongqiao Liu
doaj   +2 more sources

The influence of cyclic loading-unloading rates on the uniaxial mechanical anisotropy of coal

Scientific Reports
In this study, the influence of the loading-unloading rate on the uniaxial mechanical anisotropy of coal was investigated via uniaxial compressive tests, acoustic emission (AE) monitoring, digital image correlation (DIC), and a series of coal specimens ...
Duo Xu, Honghua Song, Like Zhao, Guoqing Tang, Shide Hu, Chenxi Duan, Yunting Song   +6 more
doaj   +3 more sources

Coupled effect of unloading rate and water content on mortar under differential cyclic loading. [PDF]

Sci Rep
Repeated excavation and fluctuations in water levels subject mortar to varying stress rates and moisture conditions; however, the coupling effects of these factors remain insufficiently studied. This research examines the combined influence of unloading rate and water content on the mechanical behavior of water-bearing mortar (WM) under multi-level ...
Liu Z, Cao P, Liu L, Wang F, Han D, Xu C.   +5 more
europepmc   +4 more sources

Impacts of Cyclic Loading and Unloading Rates on Acoustic Emission Evolution and Felicity Effect of Instable Rock Mass

Advances in Materials Science and Engineering, 2018
Uniaxial cyclic loading-unloading compression experiments with schemes of six loading rates and six unloading rates were carried out on the combined testing platform. Impact of loading and unloading rates on rock AE characteristics was revealed.
Mingwei Zhang, Qingbin Meng, Shengdong Liu, Deyu Qian, Nong Zhang   +4 more
doaj   +2 more sources

Effect of stress unloading rate on fine-scale deformation mechanism of rock under high osmotic pressure

Frontiers in Earth Science
To explore the influence of the working face excavation rate on the rock deformation mechanism and seepage characteristics, deformation and seepage tests of sandstone under different loading and unloading stress paths, such as constant axial pressure ...
Weiji Sun, Xu Qin, Qiang Liu, Qiang Liu, Yujun Zhang, Wenfei Ma, Yangqi Ma, Jingang Gao, Jingang Gao   +8 more
doaj   +2 more sources

Experimental Investigation on Unloading-Induced Sliding Behavior of Dry Sands Subjected to Constant Shear Force

Applied Sciences
Infilled joints or faults are often subjected to long-term stable shear forces, and nature surface processes of normal unloading can change the frictional balance.
Wengang Dang, Kang Tao, Jinyang Fu, Bangbiao Wu   +3 more
doaj   +2 more sources