Numerical Investigation on Factors Influencing the Time-Dependent Stability of the Rock Slopes with Weak Structure Planes

2013 ◽  
Vol 353-356 ◽  
pp. 177-182
Author(s):  
Lian Chong Li ◽  
Shao Hua Li
Keyword(s):  
Rock Mass ◽  
Rock Slope ◽  
Failure Time ◽  
Time Dependent ◽  
Catastrophic Failure ◽  
Long Term Stability ◽  
Stability Of Slopes ◽  
Factors Influencing ◽  
Weak Structure

Under the combined effects of various external factors, such as temperature, seepage, alternate wetting and drying and so on, the mechanical properties of rock mass are susceptible to be deteriorated, and its strength characteristics are significantly degraded with time. The mesoscopic damage accumulated inside the rock, contributing the rock slope instability with weak structure planes, generate the time-dependent deformation, and eventually lead to the slope failure. Given the time-dependent deformation of the rock, numerical simulations are conducted to investigate the key factors influencing the long-term stability of slopes. Numerical results show that the catastrophic failure time of slopes is linear to its cohesion, and the bigger cohesion and friction angle increase catastrophic failure time, i.e., the stability of rock slope increase. In addition, the configuration of the intact rock bridge can also influence the time-dependent slope stability. Slope height can significantly affect the slope stability and the maximum horizontal displacement. Differences in rock mass storage environment play an important role in the long-term stability of slopes.

Rheological Characteristics of Weak Rock Mass and Effects on the Long-Term Stability of Slopes

2013 ◽  
Vol 47 (6) ◽  
pp. 2253-2263 ◽  
Author(s):  
Tianhong Yang ◽  
Tao Xu ◽  
Hongyuan Liu ◽  
Chunming Zhang ◽  
Shanyong Wang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Weak Rock ◽  
Rheological Characteristics ◽  
Term Stability ◽  
Long Term Stability ◽  
Stability Of Slopes ◽  
Weak Rock Mass

In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects

2004 ◽  
Vol 261-263 ◽  
pp. 1097-1102 ◽  
Author(s):  
Jian Liu ◽  
Xia Ting Feng ◽  
Xiu Li Ding ◽  
Huo Ming Zhou
Keyword(s):  
Rock Mass ◽  
Creep Behavior ◽  
Large Scale ◽  
Time Dependent ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.

scholarly journals Observation of the rock slope thermal regime, coupled with crack meter stability monitoring

2021 ◽  
Author(s):  
Ondřej Racek ◽  
Jan Blahůt ◽  
Filip Hartvich
Keyword(s):  
Rock Mass ◽  
Monitoring System ◽  
Rock Slope ◽  
Global Radiation ◽  
Environmental Parameters ◽  
Radiation Balance ◽  
Rock Types ◽  
Novel Approach ◽  
First Results

Abstract. This article describes an innovative, complex and affordable monitoring system designed for joint observation of environmental parameters, rock block dilatations and temperature distribution inside the rock mass with a newly designed 3-meter borehole temperature sensor. Global radiation balance data are provided by pyranometers. The system introduces a novel approach for internal rock mass temperature measurement, which is crucial for the assessment of the changes in the stress field inside the rock slope influencing its stability. The innovative approach uses an almost identical monitoring system at different sites allowing easy setup, modularity and comparison of results. The components of the monitoring system are cheap, off-the-shelf and easy to replace. Using this newly designed system, we are currently monitoring three different sites, where the potential rock fall may endanger society assets below. The first results show differences between instrumented sites, although data time-series are relatively short. Temperature run inside the rock mass differs for each site significantly. This is very likely caused by different aspects of the rock slopes and different rock types. By further monitoring and data processing, using advanced modelling approaches, we expect to explain the differences among the sites, the influence of rock type, aspect and environmental variables on the long-term slope stability.

scholarly journals Evaluating Long-Term Strength and Time to Failure of Sandstone with Different Initial Damage

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Rongbin Hou ◽  
Yanke Shi ◽  
Leige Xu ◽  
Jinwei Fu ◽  
Kai Zhang
Keyword(s):  
Failure Time ◽  
Term Strength ◽  
Steady Creep ◽  
Creep Failure ◽  
Damage State ◽  
Term Stability ◽  
Long Term Stability ◽  
Creep Stress ◽  
Initial Damage

Long-term strength (LTS) of rock materials is important for the long-term stability analysis and the failure prediction of structures in rock engineering. Numerous studies have been carried out on the LTS for various kinds of rock; however, the effects of initial damage on the LTS and creep failure time of rock have not been conducted. In the present study, the creep experiment with controllable initial damage state of rock was designed. Then, the LTS of rock specimens with different initial damage was determined by four methods (i.e., the isochronous stress-strain curve method, the steady creep discriminated method, the volumetric strain inflexion point determined method, and the intersection of the steady creep rate method). The results show that, with the increase in the initial damage, the LTS of rock decreases and the relationship between the initial damage and the LTS of rock can be described as a linear function. Finally, an evaluation method for predicting the creep failure time of rock under a single stress level was proposed. In addition, the creep failure time of rock with different initial damage under different creep stress levels was obtained by the method. The results indicate that both the initial damage and the creep stress levels have a great influence on creep failure time, i.e., greater initial damage or creep stress leads to a shorter period for rock failure. Thus, for analyzing the long-term stability of rock mass structure, not only the influence of in situ stress but also the initial damage state of the surrounding rock should be considered.

TIME-DEPENDENT RISK FACTORS INFLUENCING THE LONG-TERM OUTCOME IN LIVING RENAL ALLOGRAFTS

2001 ◽  
Vol 72 (5) ◽  
pp. 941-947 ◽  
Author(s):  
Hiroshi Toma ◽  
Kazunari Tanabe ◽  
Tadahiko Tokumoto ◽  
Tomokazu Shimizu ◽  
Hiroaki Shimmura
Keyword(s):  
Risk Factors ◽  
Time Dependent ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Renal Allografts ◽  
Factors Influencing

scholarly journals Factors influencing mechanical long-term stability of condensation curing silicone elastomers

2020 ◽  
Vol 27 (11) ◽  
Author(s):  
Alena Jurásková ◽  
Kim Dam-Johansen ◽  
Stefan Møller Olsen ◽  
Anne Ladegaard Skov
Keyword(s):  
Silicone Elastomers ◽  
Term Stability ◽  
Long Term Stability ◽  
Factors Influencing

scholarly journals Design Study of Steel Fibre Reinforced Concrete Shaft Lining for Swelling Ground in Toronto, Canada

2021 ◽  
Vol 11 (8) ◽  
pp. 3490
Author(s):  
Min Seong Kim ◽  
Sean Seungwon Lee
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
Time Dependent ◽  
Fibre Reinforced Concrete ◽  
Swelling Behaviour ◽  
Steel Fibre Reinforced Concrete ◽  
Long Term Stability ◽  
Shaft Lining ◽  
Installation Time

Reinforced concrete (RC) is a widely used construction material around the world. RC has many advantages in terms of structural stability. However, the reinforcement of RC requires extensive labour costs. Steel fibre reinforced concrete (SFRC) has been widely studied to replace steel bars in concrete structures over the decades. However, most underground structures, such as tunnel lining, are usually designed using conventional RC for long-term stability due to unexpected geotechnical characteristics, such as directional and depth-dependent varied lateral pressure, earthquakes, groundwater, and time-dependent swelling behaviour. In this paper, an alternative design of shaft structure using SFRC, based on the original RC designed data in the Toronto region, was studied to evaluate the feasibility of SFRC replacing conventional RC. A key geological feature of the site is that the bedrock is comprised of Georgian Bay shale, which exhibits long-term time-dependent deformation (TDD). The capacities of RC and SFRC for the shaft lining were calculated based on the Canadian concrete design codes CSA A23.3 and RILEM TC 162-TDF, to assess the benefit of adding steel fibre, and several analytical solutions were used to calculate the applied load on the lining. A specialised TDD constitutive model in Fast Lagrangian Analysis of Continua (FLAC) 2D was developed to estimate whether the optimum installation time of the shaft lining, based on the geological reports, is appropriate under swelling behaviour, and evaluate the resultant long-term stability. The calculated hoop thrust and bending moment for several loading cases were within the capacity of the SFRC shaft lining. The numerical analysis demonstrated that the proposed lining installation time could be reduced, despite consideration of the long-term TDD behaviour.

scholarly journals Study on the Creep Constitutive Model of a Sandstone Rock under the Water-Rock Interaction

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zuosen Luo ◽  
Zuoxiang Zhu ◽  
Jianlin Li ◽  
Lehua Wang ◽  
Qiao Jiang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Nonlinear Creep ◽  
Rock Interaction ◽  
Long Term Stability ◽  
Sandstone Rock ◽  
Influence Of Water ◽  
Creep Constitutive Model ◽  
Water Rock Interaction

With the continuous construction of large-scale geotechnical engineering, more and more attention has been paid to the long-term stability of rock mass engineering, especially the problem of rock creep under the influence of water. Combined with the author’s previous research on the triaxial creep characteristics of sandstone under water-rock interaction, a nonlinear creep constitutive model was established to capture the degradation behavior of a sandstone rock due to cyclic wetting and drying of the reservoir water. Due to the limitations of the visco-elastoplastic model, a thorough modification was done to account the effect of the water-rock interaction on the mechanical degradation of the sandstone rock. Finally, the predicted results were proved to be in a good agreement with the experimental results. Moreover, the strong correlations between the predicted results and the experimental results show the effectiveness of the modified model to scrutinize the nonlinear creep behavior of sandstone rock. Relevant research results have important theoretical significance for the accurate prediction and effective control of the long-term stability of rock mass engineering under the influence of water-rock interaction.

scholarly journals A Nanoindentation Approach for Time-Dependent Evaluation of Surface Free Energy in Micro- and Nano-Structured Titanium

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 287
Author(s):  
Serena De Santis ◽  
Edoardo Rossi ◽  
Marco Sebastiani ◽  
Simona Sennato ◽  
Edoardo Bemporad ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Free Energy ◽  
High Resolution ◽  
Sample Preparation ◽  
Surface Free Energy ◽  
Time Dependent ◽  
Long Term Stability ◽  
Titanium Surfaces ◽  
Non Destructive

Surface free energy (SFE) of titanium surfaces plays a significant role in tissue engineering, as it affects the effectiveness and long-term stability of both active coatings and functionalization and the establishment of strong bonds to the newly growing bone. A new contact–mechanics methodology based on high-resolution non-destructive elastic contacting nanoindentation is applied here to study SFE of micro- and nano-structured titanium surfaces, right after their preparation and as a function of exposure to air. The effectiveness of different surface treatments in enhancing SFE is assessed. A time-dependent decay of SFE within a few hours is observed, with kinetics related to the sample preparation. The fast, non-destructive method adopted allowed for SFE measurements in very hydrophilic conditions, establishing a reliable comparison between surfaces with different properties.

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