scholarly journals Deformation Process and Mechanism Analyses of a Rock Slope Based on Long-Term Monitoring at the Pubugou Hydropower Station, China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Xuefeng Mei ◽  
Nengfeng Wang ◽  
Guotao Ma ◽  
Jie Wang ◽  
Yan Wang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Rock Slope ◽  
Fractured Rock ◽  
Road Construction ◽  
Hydropower Station ◽  
Small Scale ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Deformation And Failure ◽  
Concrete Frame

This paper presents a typical 450 m high rock slope in a highly jointed and fractured rock mass at Pubugou (PBG) hydropower station on the Dadu River. We established a set of multiphase field geological survey combined with GPS, inclinometers, and piezometer monitoring system to analyze the deformation and failure mechanism of rock slope. The results show that small-scale excavation in road construction disrupted the balance of the Pubugou rock slope (PBGRS), and several local retrogressive failures occurred at the toe. Monitoring data regarding surface and subsurface movements show that the PBGRS is stable as a whole. The deformation concentrated mainly in the loosened fractured zone, which was a feature with sliding-compression cracking. Highly loosened rock mass was the predominant factor affecting the stability of the PBGRS, while the role of reservoir water level fluctuation, though positive, was not significant. Overall, the PBGRS still has a high potential for further development, especially in the slope’s upper zone. To reinforce the slope, measurements mainly consist of the concrete frame combined with anchor cables constructed on the slope. In this study, the analysis was carried out of pre- and postreinforcement measure slope stability with numerical simulation, and safety factor increased from 1.09 to 1.21. This study’s findings have important implications to the analytical method and reinforcement design with geological settings like that of the PBGRS.

A New Method to Determining the Strength Parameters of Fractured Rock Mass

2014 ◽  
Vol 898 ◽  
pp. 378-382
Author(s):  
Yun Hua Guo ◽  
Wei Shen Zhu
Keyword(s):  
Rock Mass ◽  
Mechanical Response ◽  
Fractured Rock ◽  
Fracture Network ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Constitutive Relationship ◽  
Hydropower Station ◽  
Rock Masses ◽  
Fractured Rock Mass

A Hydropower Station is located in the middle reach of the Dadu River in southwest China. The natural slope angles are generally 40°~65° and the relative elevation drop is more than 600m. Complex different fractures such as faults, dykes and dense fracture zones due to unloading are developed. Many abutment slopes were formed during construction of the abutments. The stability of these steep and high slopes during construction and operation period plays an important role for the safe construction and operation of the hydropower station. According to the statistical distribution of joints and fractures at the construction site, the slope is divided into a number of engineering geological zones. For each zone, a stochastic fracture network and a numerical model which is close to the real state of the fractured rock mass are established by the Monte-Carlo method. The mechanical response of fractured rock masses with different sizes of numerical models is studied using FLAC3D. The REV characteristic scale is identified for rock masses in the slopes with stochastic fracture network. Numerical simulation is performed to obtain the stress-strain curve, the mechanical parameters and the strength of the jointed rock mass in the zone. A constitutive relationship reflecting the mechanical response of the jointed rock mass in the zone is established. The Comparison between the traditional method and the method in this paper has been made at the end.

scholarly journals GEOTECHNICAL INVESTIGATION OF THE ROCK SLOPE STABILITY PROBLEMS OCCURRED AT THE FOUNDATIONS OF THE COASTAL BYZANTINE WALL OF KAVALA CITY, GREECE

2017 ◽  
Vol 43 (3) ◽  
pp. 1230 ◽  
Author(s):  
C. Loupasakis ◽  
N. Spanou ◽  
D. Kanaris ◽  
D. Exioglou ◽  
A. Georgakopoulos
Keyword(s):  
Rock Mass ◽  
Rock Slope ◽  
Fractured Rock ◽  
Rock Slope Stability ◽  
Normal Faults ◽  
Sea Waves ◽  
Coast Line ◽  
Support Measures ◽  
Wave Erosion ◽  
Very High

The coastal Byzantine wall of Kavala is located at the Panagia peninsula and it is founded on the Simvolou granite. The granite rock mass appears to be fractured by joint sets with very high persistence (>20m) and very wide spacing (60cm – 2m), forming large rock blocks. Further more, the Panagia peninsula is intersected by numerous parallel normal faults, forming extended zones of intensively fractured rock mass. Along the coastline the granite appear to be eroded by the sea waves, forming small gulfs around the faults. The Byzantine wall is founded along the edge of the fractured slopes forming the coast line of the peninsula, arising issues about the safety of the historical construction. The joint sets form numerous rock wedges with unfavourable orientation, many sections of the slopes are undercut by the wave erosion and in the majority of the fault zones the rock mass presents intensive fragmentation. The above described condition of the rock mass was recorded in detail along the entire coast line and all unstable sections were located. A full set of support measures was proposed for all unfavourable sections aiming to the improvement of the geotechnical behaviour of the rock mass, constituting the foundation formation of the Byzantine wall.

Deformation and stability analyses of a near-dam rocky slope and its potential landslide-generated wave threats

2021 ◽  
pp. qjegh2021-018
Author(s):  
Ming-liang Chen ◽  
Xing-guo Yang ◽  
Shun-chao Qi ◽  
Hai-bo Li ◽  
Jia-wen Zhou
Keyword(s):  
Water Level ◽  
Rock Slope ◽  
Limit Equilibrium ◽  
Water Levels ◽  
Reservoir Rock ◽  
Water Diversion ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Impact

Occurrence of a reservoir landslide and its potential secondary hazards near a dam can result in significant losses and casualties, such as those that resulted from the Vajont landslide. In this study, a cataclinal rock slope in the Maoergai reservoir was taken as a case to study the characteristics of the gravitational deformation process and to analyze the potential threat. The stability of rock slope is analyzed by the limit equilibrium method, and the potential landslide movement and subsequent waves are also simulated. Results indicate that lithology, geological structure, reservoir water level changes and artificial activities all play an important role for the large deformation of rock slope deformation, which is characterized by a combination of bending-toppling and principally shear-slip. Pre-calculations of potential threats indicated that the impact of a landslide wave would be greater at dead water levels than at the normal water level and could result in blockage of the inlet to the water diversion structure on the opposite right bank. These findings provide implication for the control of reservoir rock slopes: (i) serious attention should be paid to the influence of water on rock strength in early and (ii) infiltration must be prevented during water level rise.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

scholarly journals Stability Assessment of the Excavated Rock Slope at the Dagangshan Hydropower Station in China Based on Microseismic Monitoring

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
K. Ma ◽  
N. W. Xu ◽  
Z. Z. Liang
Keyword(s):  
Rock Mass ◽  
Slope Stability ◽  
Monitoring System ◽  
Rock Slope ◽  
Rock Slope Stability ◽  
Hydropower Station ◽  
Bank Slope ◽  
The Stability ◽  
The Right ◽  
Dagangshan Hydropower Station

A high-resolution microseismic (MS) monitoring system was implemented at the right bank slope of the Dagangshan hydropower station in May 2010 to analyse the slope stability subjected to continuous excavation. The MS monitoring system could real-time capture a large number of seismic events occurring inside the rock slope. The identification and delineation of rock mass damage subject to excavation and consolidation grouting can be conducted based on the analysis of tempospatial distribution of MS events. However, how to qualitatively evaluate the stability of the rock slope by utilizing these MS data remains challenging. A damage model based on MS data was proposed to analyse the rock mass damage, and a 3D finite element method model of the rock slope was also established. The deteriorated mechanical parameters of rock mass were determined according to the model elements considering the effect of MS damage. With this method, we can explore the effect of MS activities, which are caused by rock mass damage subjected to excavation and strength degradation to the dynamic instability of the slope. When the MS damage effect was taken into account, the safety factor of the rock slope was reduced by 0.18 compared to the original rock slope model without considering the effect. The simulated results show that MS activities, which are subjected to excavation unloading, have only a limited effect on the stability of the right bank slope. The proposed method is proven to be a better approach for the dynamical assessment of rock slope stability and will provide valuable references for other similar rock slopes.

Stability Analysis of Dangerous Rocks on the Slope of a Hydropower Station

2013 ◽  
Vol 405-408 ◽  
pp. 621-629 ◽  
Author(s):  
Hai Feng Li ◽  
Guo Xing Zhang ◽  
Tao Huang ◽  
Qiu Jing Zhou
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Discontinuous Deformation Analysis ◽  
Hydropower Station ◽  
Deformation Analysis ◽  
Time Interval ◽  
Block Method ◽  
Fractured Rock Mass ◽  
Unstable Failure ◽  
The Stability

Dangerous rocks are among the most significant factors in analyzing the stability of high slopes, and are the main geological hazards on such slopes. These rocks are typical spatial blocks. The unstable failure of dangerous rocks poses evident spatial features. Consequently, their stability should be calculated by considering it as a three-dimensional (3-D) problem. In this research, the general block method of fractured rock mass and 3-D discontinuous deformation analysis (DDA) are used to study the stability of dangerous rocks on the slope of a hydropower station. The general block method of fractured rock mass is used to generate dangerous rocks and to assess the geometric mobility of blocks. The progressive unstable failure of dangerous rocks is also analyzed. Moreover, 3-D DDA is implemented to examine the stability of dangerous rocks, including the regularity of their unstable failure. The failure sequence of each batch of blocks estimated by general block theory is the same as that in the results of 3-D DDA. The decrease in the shear parameters of the structural plane shortens the time interval of failures, but increases the number and capacity of blocks.

scholarly journals A study of tensile strength of fractured rock mass by phase field method in DEAL.II with local refinement technique

2020 ◽  
Vol 71 (7) ◽  
pp. 737-745
Author(s):  
Dang Hong Lam
Keyword(s):  
Tensile Strength ◽  
Rock Mass ◽  
Phase Field ◽  
Fractured Rock ◽  
Mechanical Energy ◽  
Field Method ◽  
Phase Field Method ◽  
Small Scale ◽  
Local Refinement ◽  
Fractured Rock Mass

Cracking propagation in elastic and porous media is still challenge topics in mechanical, energy, and environmental engineering. In this paper, the phase field method will be used to model the cracking propagation at the small scale for elastic media. This method is doing well in DEAL.II with the help of local refinement technique which allows studying the tensile strength of fractured rock mass behavior without prior knowledge of cracking propagation path and reduction of computational consumption. This implementation is applied to model a fractured rock mass in which a plenty of explicit fractures are distributed though total energy released by Griffith's criterion. Through these applications, we demonstrate and highlight the performance of the phase field method with local refinement technique in modeling crack propagation as well as investigate the tensile strength of fractured rock mass dependency its crack orientation

Comparative Analysis of Reinforcement Programs of System Anchors for Unloading Rock Slope

2011 ◽  
Vol 374-377 ◽  
pp. 2312-2315
Author(s):  
Yi Sheng Huang ◽  
Qi Jun Zhu ◽  
Li Jun Zhang
Keyword(s):  
Rock Mass ◽  
Comparative Analysis ◽  
Constitutive Model ◽  
Rock Slope ◽  
Slope Deformation ◽  
Hydropower Station ◽  
Nonlinear Elastic ◽  
The Impact

Based on hyperbolic nonlinear elastic constitutive model of unloading rock mass, the anchoring rock mass of excavation spillway of a hydropower station has been taken for the study. And considering the impact of excavation unloading process, three reinforcement programs are compared and analyzed. Overall, the constraint by system anchors on deformation of the spillway slope is limited. If the limit on the slope deformation is higher, pre-stressed cables are necessary.

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