Three Dimensional Numerical Analysis of Deformation and Stability of Zone II of Xiazanri Slope Deposit

2011 ◽  
Vol 90-93 ◽  
pp. 2372-2379
Author(s):  
Li Fang Zou ◽  
Wei Ya Xu ◽  
Chong Shi
Keyword(s):  
Large Scale ◽  
Failure Modes ◽  
Three Dimensional ◽  
Left Bank ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Geological Conditions ◽  
Normal Water ◽  
Zone Ii ◽  
Very High

Xiazanri Slope is a large-scale deposit slope located at the left bank of Liyuan hydropower station in Southwest China. The construction of the water intake there will form a very high excavation slope. Possible failure modes are analyzed based on geological conditions. Numerical simulation is conducted in FLAC3D to obtain the deformation and failure characteristics of slope under excavation and normal water table conditions. Strength reduction method is used to obtain factor of safety. Results show the overall deposit is stable and attention should be paid to local parts.

scholarly journals Shell-crossing in a ΛCDM Universe

2020 ◽  
Vol 501 (1) ◽  
pp. L71-L75
Author(s):  
Cornelius Rampf ◽  
Oliver Hahn
Keyword(s):  
Dark Matter ◽  
Perturbation Theory ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Three Dimensional ◽  
Random Initial Data ◽  
Recursion Relations ◽  
Indispensable Tool ◽  
First Time ◽  
Very High

ABSTRACT Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this, we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed at large orders reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.

scholarly journals Problems of mineral raw material losses of quality and quantity management in developing of large-scale complex-structure deposits.

2018 ◽  
Vol 56 ◽  
pp. 04003
Author(s):  
Sergei Tkach
Keyword(s):  
Large Scale ◽  
Raw Materials ◽  
Complex Structure ◽  
Raw Material ◽  
Qualitative And Quantitative ◽  
Mineral Raw Material ◽  
Regulatory Documents ◽  
Geological Conditions ◽  
High Degree ◽  
Very High

The article deals with the problems of mineral raw material losses of quality and quantity management in developing of large-scale complex-structure and composition deposits of solid minerals. It is shown that a very high degree of mining and geological conditions variability in time and space for the development of mining units is typical for such deposits. This significantly complicates the qualitative and quantitative operating losses setting and accounting of mineral raw materials during its extraction in the framework of existing general and industry regulatory documents. Conceptual principles for face-by-face operational setting of losses and impoverishment of minerals for the conditions of bulk mining of complex-structure deposits with the formation of gross mining flow with economically feasible and specified level of quality (the content of commercial and harmful components) are stated. These principles generally do not contradict effective instructions main provisions and are made to minimize the total operating losses during the processing of several mine sections (faces).

scholarly journals Key Factors Affecting the Deformation and Failure of Surrounding Rock Masses in Large-Scale Underground Powerhouses

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Meng Wang ◽  
Jia-wen Zhou ◽  
An-chi Shi ◽  
Jin-qi Han ◽  
Hai-bo Li
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Surrounding Rock ◽  
Rock Masses ◽  
Affecting Factors ◽  
Key Factors ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Factors Affecting ◽  
Geological Conditions

The stability of the surrounding rock masses of underground powerhouses is always emphasized during the construction period. With the general trends toward large-scale, complex geological conditions and the rapid construction progress of underground powerhouses, deformation and failure issues of the surrounding rock mass can emerge, putting the safety of construction and operation in jeopardy and causing enormous economic loss. To solve these problems, an understanding of the origins and key affecting factors is required. Based on domestic large-scale underground powerhouse cases in the past two decades, key factors affecting the deformation and failure of the surrounding rock mass are summarized in this paper. Among these factors, the two most fundamental factors are the rock mass properties and in situ stress, which impart tremendous impacts on surrounding rock mass stability in a number of cases. Excavation is a prerequisite of surrounding rock mass failure and support that is classified as part of the construction process and plays a pivotal role in preventing and arresting deformation and failure. Additionally, the layout and structure of the powerhouse are consequential. The interrelation and interaction of these factors are discussed at the end of this paper. The results can hopefully advance the understanding of the deformation and failure of surrounding rock masses and provide a reference for design and construction with respect to hydroelectric underground powerhouses.

scholarly journals Deformation and Failure Analyses of the Surrounding Rock Mass with an Interlayer Shear Zone in the Baihetan Underground Powerhouse

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Fei Yuan ◽  
An-chi Shi ◽  
Jia-wen Zhou ◽  
Wang-bing Hong ◽  
Meng Wang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Shear Deformation ◽  
Shear Zone ◽  
Failure Modes ◽  
Shear Zones ◽  
Surrounding Rock ◽  
Left Bank ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Interlayer Shear

In the process of underground cavern excavation, the existence of the interlayer shear zones or large faults often makes the surrounding rock tend to be unstable or even deformed. Under the influence of interlayer shear zone C2, different degrees of deformation and failure occurred in many parts during the excavation of the Baihetan left bank underground powerhouse. Based on field monitoring and numerical calculation, this paper studies the deformation and failure characteristics of the rock mass with C2 in the whole excavation process and the failure mechanisms are analyzed. The results show that C2 has poor mechanical properties. In the process of excavation, it mainly induces two failure modes: rock collapse and shear deformation, which specifically leads to rock collapses, large deformation and shotcrete cracking in the main powerhouse, and shear deformation in the omnibus bar caves. In addition, the similarities and differences between this study and other studies on the deformation and failure of surrounding rock of underground powerhouse in recent years are discussed, and the relevant treatment measures for C2 are given. The above research results can be a reference for other related studies.

scholarly journals Deformation Analysis of Large-Scale Rock Slopes Considering the Effect of Microseismic Events

2019 ◽  
Vol 9 (16) ◽  
pp. 3409 ◽  
Author(s):  
Linlu Dong ◽  
Ying Yang ◽  
Bo Qian ◽  
Yaosheng Tan ◽  
Hailong Sun ◽  
...  
Keyword(s):  
Large Scale ◽  
Rock Fracture ◽  
Three Dimensional ◽  
Seismic Source ◽  
Microseismic Monitoring ◽  
Deformation Analysis ◽  
Left Bank ◽  
Exploratory Research ◽  
Rock Slopes ◽  
Bank Slope

To research the macroscopic deformation of rock microseismic damage, a high-precision microseismic monitoring system was established on the left bank slope of the Baihetan hydropower station in Southwestern China. Based on the microseismic monitoring and field deformation data, the seismic source radius was applied to characterize the rock fracture scale. Numerical simulations introduced the rock micro-fracture information into the three-dimensional numerical model of the left bank slope and established the damage constitutive model. The unloading deformation process of the left bank abutment rock mass is described by numerical calculations. The feedback analysis method considering the effect of microseismic damage is preliminary exploratory research, which provides a new idea for the stability analysis of similar high rock slopes.

scholarly journals A Control Method of Rock Burst for Dynamic Roadway Floor in Deep Mining Mine

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhimin Xiao ◽  
Jun Liu ◽  
Shitan Gu ◽  
Mingqing Liu ◽  
Futian Zhao ◽  
...  
Keyword(s):  
Rock Burst ◽  
Control Method ◽  
Tectonic Stress ◽  
Surrounding Rock ◽  
Floor Rock ◽  
Deep Mining ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Working Face ◽  
Geological Conditions

Roadway floor rock burst is an important manifestation of rock bursts in deeply buried mines. With the increase of mining depth and mining intensity, rock burst disasters in the roadway floor such as floor heaves are becoming more serious. The article investigated the roadway floor severe heave caused by floor rock burst during excavation of the No. 3401 working face, which was controlled by an anticlinal structure and deep mining in Shandong Mine, China. Firstly, by analyzing geological conditions of the working face, roadway support parameters, and characteristics of coal and rock, it was revealed that high tectonic stress and high crustal stress were main causes of the floor rock burst. Secondly, based on the Theory of Mechanics and Theory of Energy, the energy conversion process in the roadway floor was discussed, and the rock burst condition caused by elastic energy in the roadway floor was analyzed. The failure characteristics of roadway-surrounding rock were also inspected, using a borehole recorder. The roof and sidewalls of roadway mainly contained fissures and cracks, whereas cracks and broken areas are distributed in the roadway floor. Finally, based on the deformation and failure characteristics of roadway-surrounding rock, a method termed “overbreaking-bolting and grouting-backfill” was proposed to control roadway floor rock burst. The method was tested in the field, and the results showed that it could effectively control the deformation of roadway floor and rock burst, guaranteeing the stability of roadway floor. This impact control method for the roadway floor can provide a reference for the prevention and control of roadway rock burst in mines with similar geological conditions.

Analysis on Causes of Deformation and Failure of Large Scale Underground Powerhouse

2011 ◽  
Vol 71-78 ◽  
pp. 644-650 ◽  
Author(s):  
Jin Yu Dong ◽  
Ji Hong Yang ◽  
Guo Xiang Yang ◽  
Fa Quan Wu
Keyword(s):  
Large Scale ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Concrete Cracking ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Underground Caverns ◽  
Geological Conditions ◽  
The Right

Jinoping No.1 is a dominant reservoir cascade hydropower station which locates at the downstream of Yalong river. The underground powerhouse locates at the right bank of the dam, lithology is marble that belongs to the second member of Zagunao group. It is constructed at region with very complicated geological conditions and high geo-stress. Concrete cracking, spalling and steel buckling and bending occurred at the downstream crown after supporting. This paper analysed the causes of deformation and failure through geological analysis and numerical simulation, and concluded that deformation and failure mainly occurred at the region where the quality of surrounding rock belongs to Ⅲ1 and had nothing to do with the unstable block cut by cracks; stress field of surrounding rock varied continueously with the proceeding of successive excavation of underground powerhouse, so the compressive stress and shear stress concentration occurred which caused the compression and shear failure of downstream crown and made it bending to the free face. It is significant to the further enforcement of this project and to the research on other similar underground caverns theoretically and practically.

scholarly journals Numerical Analyses on Deformation and Failure Characteristics of Surrounding Rock of Gob-Side Entry Retention by Roof Cutting

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Qunying Wu ◽  
Binhui Liu ◽  
Jun Yang ◽  
Yajun Wang ◽  
Kuikui Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Distinct Element ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Temporary Support ◽  
Universal Distinct Element Code ◽  
Distinct Element Code ◽  
Borehole Televiewer

Universal distinct element code (UDEC) is a simulation software based on the discrete element method, widely used in geotechnical mining. However, in the UDEC, when simulating large-scale excavation, the subsidence of the fractured zone is almost equal to the mining height, which makes the deformation value calculated in the study of gob-side entry retention too large. To solve this problem, in this paper, the double-yield constitutive model is applied to the whole caving zone to analyze the deformation and failure characteristics of surrounding rock along gob-side entry retaining by roof cutting. The results of the simulation are in good agreement with the result of drilling peeking (drilling observation by borehole televiewer) and field condition (observation and measurement in the field). Finally, by using this numerical method, the effects of roadway width, temporary support, and coal side support on the failure of the roof and the arc coal side are studied.

scholarly journals Study on Mutual Feedback Mechanism and Stability Control of Toppling Slope and Tunnels with High Excavation Rate

2021 ◽  
Vol 2076 (1) ◽  
pp. 012075
Author(s):  
Huifeng Zheng ◽  
Shuo Zheng ◽  
Yi Chen ◽  
Guanye Wu ◽  
Yong Zhou
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Great Difficulty ◽  
Stability Control ◽  
Feedback Mechanism ◽  
Western China ◽  
Left Bank ◽  
Deformation Control ◽  
Geological Conditions ◽  
Horizontal Partitioning

Abstract During the construction of large-scale hydropower projects in deep mountain gorge areas of the Western China, the difficulties, such as uncontrollable large deformation, great deformation caused by small disturbance, are often encountered in the process of implementation. In particular, due to the limitation of topography, geological conditions and the layout of structures, the slope and dense tunnel group with large section need to be excavated simultaneously in the toppling rock mass. The feedback action mechanism between slope and tunnel excavation is complicated and the deformation control of toppling rock is difficult, which leads to great challenges to engineering construction. In MW hydropower project in west of China, the intake slope, the spillway channel slope, four headrace tunnels, and the sand flushing tunnel, as well as the construction traffic tunnel are arranged in Huishi Ridge on the left bank, where two high slopes and six lager cross-section tunnels are simultaneously excavated and the excavation rate in the toppling deformation rock mass is over 50%, moreover, the lateral coverage thickness of tunnel body is less than the diameter of the tunnel, which leads to the great difficulty of stability control. The excavation stability and safe of the thin mountain ridge is the vital issue to the success of the whole project. Based on the study of the physical and mechanical parameters of toppling rock mass of MW HPP, the mutual feedback mechanism of toppling slope and tunnel group is revealed, an excavation method involving horizontal partitioning, vertical layering, reserving rock plug and reasonable skipping warehouse is proposed. Monitoring results shows that the slope and surrounding rock of the tunnels are stable during the operation period. The research of this paper based on the MW HPP can provide reference for other similar projects.

scholarly journals Crack Initiation, Propagation, and Failure Characteristics of Jointed Rock or Rock-Like Specimens: A Review

2019 ◽  
Vol 2019 ◽  
pp. 1-31 ◽  
Author(s):  
Ri-hong Cao ◽  
Ping Cao ◽  
Hang Lin ◽  
Xiang Fan ◽  
Chunyang Zhang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Crack Initiation ◽  
Failure Modes ◽  
Failure Process ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Failure Behavior ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Natural Rock

Rock masses are heterogeneous materials containing a large number of discontinuities, and the failure of the natural rock mass is induced by the crack propagation and coalescence of discontinuities, especially for the rock mass around tunnel or underground space. Because the deformation or failure process of jointed rock mass exhibits strongly nonlinear characteristics, it is also very difficult to predict the strength and failure modes of the rock mass. Therefore, it is very necessary to study the failure mechanisms of jointed rock mass under different stress conditions. Apart from the stress condition, the discontinuities geometry also has a significant influence on the mechanical behavior of jointed rock mass. Then, substantial, experimental, and numerical efforts have been devoted to the study of crack initiation, propagation, and coalescence of rock or rock-like specimens containing different kinds of joints or fissures. The purpose of this review is to discuss the development and the contribution of the experiment test and numerical simulation in failure behavior of jointed rock or rock-like specimens. Overall, this review can be classified into three parts. It begins by briefly explaining the significance of studying these topics. Afterwards, the experimental and numerical studies on the strength, deformation, and failure characteristics of jointed rock or rock-like materials are carried out and discussed.

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