FU Zhiliang¹, GUO Hua², GAO Yanfa³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.3, pp. 145-156, 2008, DOI:10.3970/icces.2008.005.145

Abstract This paper is focused on the micro-damage evolution properties of gray green mudstone under impacting disturbance load conditions for the first time by using the real time CT testing technique. CT images and CT values for rock cross-sections under different impacting disturbance loading levels were obtained. The paper is also to describe process of rock creep damage under disturbance loads and to explore the mechanism of micro-damage. The results have shown that rock failure is easy to happen suddenly rock is in or close to limit strength neighborhood during the process of disturbance. This will further lay the theory basis… More >

J. Gajdošík¹, M. Šejnoha¹, J. Zeman¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.2, pp. 129-136, 2007, DOI:10.3970/icces.2007.004.129

Abstract Rock masses with relatively high concentration of discontinuities or joints are considered. Being aware of limitations of various averaging techniques such as the self consistent or Mori-Tanaka methods in providing reliable estimates of generally nonlinear macroscopic response of jointed rock masses, the paper introduces a notion of statistically equivalent periodic unit cell (SEPUC). Such a unit cell contains, in order to reduce the problem complexity, of the orders of magnitude less number of joints in comparison with the actual material system. In analogy with two-phase composites, the SEPUC is expected to be found in a statistical sense by matching suitable… More >

Longgang Tian^1,2,*, Xiao Wang^1,2, Qi Zhang^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.2, pp. 30-30, 2019, DOI:10.32604/icces.2019.04809

Abstract Various defects such as cracks and holes exist in coal-rock body and they have a large influence on the mechanical properties of coal-rock. Therefore, it is of great significance to study the fracture characteristics in order to understand the instability mechanism of coal body. In this study, a variety of defective coal-rock specimens with different cracks and holes were established by PFC software, and then the characteristics of stress-strain and crack evolution law of coal-rock were studied. Results show that the mechanical properties, crack propagating characteristics, propagation forms of initial crack and final crack distributions of coal-rock specimens with different… More >

Zixin Zhang^1,2,*, Shuaifeng Wang^1,2, Xin Huang^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.2, pp. 29-29, 2019, DOI:10.32604/icces.2019.04704

Abstract Block theory is widely used in numerical simulation of rock engineering due to its concision and fast-calculation. The paper proposes block theory for TBM (tunnel boring machine) tunnels to extend the traditional block theory applicative for tunnels excavated by TBM. In the proposed method, TBM-block interaction forces are taken into consideration. Subsequently, an index is proposed to estimate the stability of the TBM tunnel based on safety factor at every given chainage of the tunnel. Finally, a real water-conveyance tunnel project is studied with block theory for TBM tunnels. The simulation results include the joint characterization, classification identification of different… More >

Liang Wu¹, Xiaorui Xiang¹, Yang Chen¹, Karrech Ali^2,*, Junru Zhou^1,*, Ming Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 421-443, 2019, DOI:10.32604/cmes.2019.05218

Abstract During the excavation of deep rock, a sudden change in boundary conditions will cause the in-situ stress on the excavation surface to release instantaneously. This disturbance propagates in the form of an unloading stress wave, which will enlarge the damage field of surrounding rock. In this paper, the dynamic unloading problem of the in-situ stress in deep rock excavation is studied using theoretical, numerical, and experimental methods. First, the dynamic unloading process of rock is analyzed through adopting the wave equation, and the equivalent viscous damping coefficient of the material is taken into consideration. Calculations show that there is significant… More >

Peixian Li^1,*, Zhixiang Tan², Lili Yan³

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.2, pp. 231-250, 2018, DOI:10.31614/cmes.2018.02573

Abstract In order to prolong the life cycle of the coal mine, Jinggezhuang (‘JGZ’) coal mine decided to excavate the shaft pillar. The first panel 0091 was designed near the pillar boundary as an experiment in shaft pillar mining. Both probability integral method (PIM) and FLAC^3D were used to evaluate the influence on the shaft safety. PIM parameters were obtained from previous surface subsidence station. The rock property is based on the lab mechanical test. A simulated FLAC^3D model containing shafts and a panel was built based on stratigraphic information. Surface subsidence results of PIM show that the 0091-panel excavation has… More >

Yiyu Lu¹, Chenpeng Song^1,2, Yunzhong Jia¹, Binwei Xia¹, Zhaolong Ge¹, Jiren Tang¹, Qian Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.1, pp. 69-86, 2015, DOI:10.3970/cmes.2015.105.069

Abstract In underground coal mines, hydrofracture can cause the increase of breathability in the fractured coal bed. When the hydrofracture crack propagates to the interface between the coal bed and the roof-floor stratum, the crack may enter roof-floor lithology, thus posing a limit on the scope of breathability increase and making it difficult to support the roof and floor board for subsequent coal mining. In this work, a two-dimensional model of coal rock bed that contains hydrofracture crack was constructed. Then an investigation that combines the fracture mechanics and the system of flow and solid in rock failure process analysis (RFPA2D-Flow)… More >

Dan Dumitriu¹, Ligia Munteanu¹, Cornel Brişan², Veturia Chiroiu¹, Rǎzvan-Vlad Vasiu², Octavian Melinte¹, Victor Vlǎdǎreanu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.2, pp. 159-173, 2013, DOI:10.3970/cmes.2013.094.159

Abstract The continuum modeling of tire/road vibro-contact dynamics is developed in this paper by assuming continuum relationship between the contact force and the deformation. An important aspect of this model is that the damping depends on the indentation. In the continuum approach, no difference is made between impact and contact, and the friction law can be other than the Coulomb’s law. Since the road is rocky, a bristle model was chosen to take into account the effect of the road irregularities. The identification of the contact domain is performed by checking the minimum distance between bodies. More >

Hui Zhang¹, Deli Gao^1,2, Xiaopin Xie¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 47-64, 2013, DOI:10.3970/cmes.2013.090.047

Abstract In oil & gas drilling engineering, the rock breaking efficiency as well as the trajectory of the Well should be quantitatively and accurately described by an ideal triaxial Rate of Penetration (ROP) model, taking into account the various objective and subjective factors. However, with the existing triaxial ROP models, it is difficult to achieve these goals. The applications of the existing ROP models are limited, especially in under-balanced drilling (air drilling, foam drilling etc.), because the unloading effect (i.e. the effect of the bottom hole differential pressure on the formation force) has been rarely considered. On the basis of a… More >

Y.J. Ning^1,2,3, Z.Y. Zhao³, J.P. Sun³, W.F. Yuan^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.3, pp. 221-262, 2012, DOI:10.3970/cmes.2012.089.221

Abstract In this paper, wave propagations in jointed rock masses are modeled by the discontinuous deformation analysis (DDA) method. The selection of the numerical control parameters in the DDA for wave propagation modeling is discussed in detail, and the effects of the joint stiffness, the seismic loading frequency, the joint strength, and the incident angle on the propagations of stress waves in a jointed rock mass are modeled and analyzed. Two nonreflecting boundary conditions including the viscous boundary condition (VBC) and the superposition boundary condition (SBC) are coupled into the DDA. The applicability of the two nonreflecting boundary conditions for simple… More >