Papers by Author: Shu Cai Li

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Authors: Wei Shen Zhu, Jian Hua Liu, Shu Cai Li
Abstract: A brief description is given to the visco-plastic constitutive model of 3-D FLAC software and some treating methods for the numerical analysis. The excavation steps and the exerting time of excavation loads are determined in the light of the real construction process. The rockmass mechanical parameters are determined according to back analysis of in-situ measured displacement data. The analysis results of displacement and stability of the opening complex surrounding rocks in the construction process and in a long period of time after excavation completion are given.
1473
Authors: Xiao Jing Li, Wei Min Yang, Wei Shen Zhu, Shu Cai Li, Ai Hua Sun
Abstract: The jointed rock mass distributed in the nature widely and its mechanical characteristic influenced the stability of the rock engineering badly. The cracks propagated and coalesced each other and macroscopic failure happened. Bolts were a kind of effective reinforcement instrument and they could prevent the cracks from propagating. However, the anchoring mechanism of bolts was not realized clearly and their reinforcement could not be reflected effectively in the numerical simulation yet. Based on the damage mechanics, a constitutive relation and damage equation of anchored jointed rock mass were presented in this paper. With a project application, the model was proved to be feasible one.
657
Authors: Wei Shen Zhu, Shu Cai Li, R.H.C. Wong, K.T. Chau, Jian Xu
225
Authors: Yu Yong Jiao, Quan Sheng Liu, Shu Cai Li
Abstract: This paper presents a three-dimensional numerical model for simulation of blocky rock structures based on static relaxation approach. The proposed method utilizes static equilibrium equations to calculate the displacements of blocks, compared to Newton’s second law applied by the traditional DEM. In order to obtain displacements simultaneously, the technique of global stiffness matrix is introduced in to form the global equilibrium equations. Because large displacements come from the accumulation of small displacement increments, an iteration procedure is adopted in the calculation. A C++ program is developed based on the proposed algorithm, and an illustrative example is computed for verification.
1391
Authors: Zhen Hao Xu, Shu Cai Li, Li Ping Li, Shao Shuai Shi
Abstract: Hydrologic and engineering geological conditions of underground engineering and mining are highly complex. Geological hazards, especially water inflow or inrush, often occur during constructions. In order to get an insight into flow state evolution laws of water inflow and inrush in karst regions, as well as the influence of tunnel excavation, a numerical simulation method was proposed with COMSOL Multiphysics. Three water flow laws, Darcy’s law, Brinkman equations and incompressible Navier-Stokes equations, are coupled and linked with each other. Water pressure and velocity can be analyzed in the course of excavation, and it can be used for further study of risk control of water inflow and inrush.
2565
Authors: Dun Fu Zhang, Wei Shen Zhu, Shu Cai Li
Abstract: By use of complex variable theory, formulae for tangential stress on ellipse edge are derived. Sub-crack point, opening angle and maximal tangential stress on ellipse edge are studied under uniaxial compression, biaxial compression, or uniaxial compression and crack water pressure separately. Based on the maximal tension stress criterion, formulas of maximal tangential stress and critical load are presented. The results show that sub-crack point, opening angle, maximal tangential stress and critical load are varied with different aspect ratio and different inclined angle. Meanwhile, the most dangerous inclined angle is obtained.
1485
Authors: Le Wen Zhang, Huai Feng Sun, Shu Cai Li, Dao Hong Qiu, De Yong Zhang
Abstract: The authors found a type of sidewall failure during the construction of a tunnel with high geostress. And relative strong rockburst usually occurred in the areas nearby during the excavation. This paper shows this type of failure called Crisp Fissure Failure and some characteristics of the failure. Reasons of the failure are also discussed. Further more, the authors studied the fracture distribution under this type of failure by Ground Penetrating Radar. Suggestions of support in a high risk tunnel are put forward based on the research of the Crisp Fissure Failure.
1661
Authors: Yong Wei Zhang, Shu Cai Li, Bo Zhang, Chun Hong Yuan, Xu Guang Chen
Abstract: Damaged mountain of Ji'nan springs city impact the landscape of the city and the surrounding and traffic along seriously, and affected the city's image and the construction of the beautiful spring city and ecological civilization seriously. They produced a new geologic disaster danger, and threaten the safety of the local people's life and property. Landscape Effect Degree (LED), as a comprehensive index, can be used to quantitatively evaluate the landscape effect degree of the damaged mountain for the city and traffic along. Study on quantitative evaluation and analysis of the impact of mountain landscape damage in Ji'nan City. Comparison and validation of the actual and damaged mountain governance work can verify the display of influence, and quantitative index for damage control plan, and ordered rectification, and the mine recovery, and treatment effect what was analyzed, and the improvement of the ecological environment analysis, and vegetation growth situation analysis vegetation ecological suitability assessment. It can provide scientific basis. Through calculation and analysis, 148 damaged mountain Ji'nan city the three districts and one line visual range, landscape effect degree very serious was 111, accounted for 75%, and severe in 31, accounting for 21%, and the general point of 3, 2%, and lighter point 3 that accounted for 2%. The evaluation results accord with the actual situation of Ji'nan, and it shows that the method for landscape evaluation is applicable.
2110
Authors: Y.S.H. Guo, R.H.C. Wong, K.T. Chau, Wei Shen Zhu, Shu Cai Li
Abstract: A number of instability problems in rock engineering projects are caused by crack propagation. However, crack growth mechanisms from 3-dimentional flaw are not fully understood, in particular for 3-D flaw case with varied dipping angle. This study focuses on 3-D surface flaw using real rock specimens containing a flaw with varied inclination angle α from axial loading and dipping angle γ from specimen surface under uniaxial compression. Acoustic emission technique was used for tracing the initiation and growth of micro-cracks inside of specimen. It was found that crack growth process is affected by the dipping angle γ of the 3-D flaw. When dipping angle γ ≠ 90º, the thickness of rock above the flaw plane is thinner than that of below the flaw plane. As a result, compressive crack and wing crack initiated easily from the thinner flaw tips. And, the normalized stress for crack initiation σi /σc, AE events and the AE energy for crack growth decreases with the dipping angle γ. However, for γ = 90º, the thickness of rock above and below of the flaw tips is the same, it was observed that anti-wing crack (crack growth direction opposite to wing crack) initiated first at a certain place away from the flaw tips, then wing crack and compressive crack emerged at the late stage. For this case, the stress σi /σc, AE events and the AE energy for crack initiation and propagation are at a high value. Thus, for rock mass contains flaws geometry with small dipping angle, some problems of crack propagation may be induced easily during excavation.
2353
Authors: Wei Shen Zhu, Yong Li, Min Yong, Q.B. Zhang, Shu Cai Li
Abstract: Geomechanics modeling has played important role in geotechnical engineering. In order to investigate on the stability of underground caverns at great depth, a large-scale geomechanics model test system was designed and manufactured. The system mainly consisted of a steel structural frame and a hydraulic loading control system, which can apply active loading on six sides with a true three-dimensional stress state. Newly developed combinational ball sliding walls were installed on each of the major loading surfaces, which were significantly reduced the friction due to model deformation. The system has apparent technical advantages such as high stiffness, great stability, and flexibility of assembly, and easy adjustment of its dimensions.
2770
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