scholarly journals Study on the Influence of Water–Rock Interaction on the Stability of Schist Slope

2020 ◽  
Vol 12 (17) ◽  
pp. 7141
Author(s):  
Qian-Cheng Sun ◽  
Can Wei ◽  
Xi-Man Sha ◽  
Bing-Hao Zhou ◽  
Guo-Dong Zhang ◽  
...  
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Structural Characteristics ◽  
Micro Structure ◽  
Intact Specimen ◽  
Rock Interaction ◽  
Structure Changes ◽  
The Stability ◽  
Water Rock Interaction

(1) The studies on the influence of rainfall on slope stability mainly focus on rainfall characteristics and the variation of strength parameters. Few studies pay attention to the micro structure changes of rock mass under long-term rainfall conditions, and the influence of failure mode. (2) Based on nuclear magnetic resonance (NMR) and electron microscopic imaging (Emmi) technology, the micro structure changes and macro deformation characteristics of the schist, under long-term immersion in different liquids are analyzed. (3) After soaking in the deionized water, the uniaxial compression strength of the intact specimen is slightly lower than that of the untreated specimens, but the test process in the elastic compression stage is considerably prolonged, and the failure modes show both shear and slip at the same time. While after soaking in acid solution, the fracture of rock samples with initial cracks can be obviously reduced and healed, which is consistent with the change of micro pore structure. The uniaxial strength and modulus of the intact samples are significantly lower, and only slip failure mode occurred. (4) It shows that water–rock interaction is an important factor influencing the stability of slope besides the external rainfall force, which affects the structural characteristics and mechanical properties of rock.

scholarly journals Effect of the Water-Rock Interaction on the Creep Mechanical Properties of the Sandstone Rock

2018 ◽  
Author(s):  
Zuosen Luo ◽  
Jianlin Li ◽  
Qiao Jiang ◽  
Yinchai Zhang ◽  
Yisheng Huang ◽  
...  
Keyword(s):  
Water Level ◽  
Term Strength ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Rock Interaction ◽  
The Three Gorges ◽  
Sandstone Rock ◽  
Water Rock Interaction

After the commencement of the Three Gorges hydropower project, the reservoir water level has been fluctuating by 30 m (145–175 m) annually. The stability of the bank slope has been highlighted since the reservoir water level has been repeated. Apart from that, the long-term effect of the water-rock interaction on the rheological and mechanical properties of the rock was not studied sufficiently. Therefore, a typical sandstone rock was brought from the Three Gorges reservoir area, to meet the purpose of this study. Then, a series of water-rock interaction tests were conducted to simulate the fluctuations in the reservoir water level. Based upon the experimental results, the following points were pointed out: 1) for the first three successive water-rock interaction cycles, the long-term strength of the rock was dramatically reduced. In contrast, the rate of reduction on the long-term strength of the rock was getting a steady state after six successive water rock interactions.2) At the failure stress level, the rock specimens exhibited similar characteristics under different water-rock interaction cycles. 3) The densely compacted micro structures of the sandstone rock were transformed into loose and porous state.

Study on the Mechanism of Water-Rock Interaction of the Black Rock Strata

2011 ◽  
Vol 243-249 ◽  
pp. 3319-3324
Author(s):  
Xin Liao ◽  
Xi Yong Wu ◽  
Jiang Tao Duan
Keyword(s):  
Immersion Test ◽  
Ecological Environment ◽  
Acidic Water ◽  
Engineering Project ◽  
Rock Interaction ◽  
Geological Characteristics ◽  
The Stability ◽  
Short Time ◽  
Rock Strata ◽  
Water Rock Interaction

Black rock strata with special engineering geological characteristics are distributed widely in different geological periods and areas. The scattered sulfide minerals in the rock strata are changed in a short time under the action of the oxygen-rich surface water and oxygen-rich groundwater. And the acidic water with strong erosiveness is formed. Then water--rock interaction between other minerals and the acidic water subsequently occurs with a series of chemical reactions. It can affect the stability of the black rocks themselves and other non-black rocks nearby directly, and cause engineering and environmental geological problems. Through the combination of engineering project and immersion test indoor, the mechanism of water-rock interaction of the black rock strata is researched. Engineering preventions and measures in the black strata region are proposed to avoid the damage to project and the ecological environment around.

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 The Dynamic Response Law of Bank Slope under Water-Rock Interaction

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yinchai Zhang ◽  
Huafeng Deng ◽  
Wei Wang ◽  
Lingling Duan ◽  
Yongyan Zhi ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Damping Ratio ◽  
Seismic Action ◽  
Loading Test ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Rock Interaction ◽  
Bank Slope ◽  
Water Rock Interaction

During the reservoir operation process, the long-term security and stability of the bank slope is affected by dynamic response characteristics of its seismic action directly. Aimed at the typical bank slope existing in the actual reservoir environment, an experiment considering reservoir water level fluctuation and soaking-air-drying cyclic water-rock interaction has been designed and conducted while the cyclic loading test was performed in different water-rock cycles. Research results indicate the following: Firstly, in the process of water-rock interaction, the dynamic characteristics of sandstone show evident degradation trend, with the increase of the damping ratio and Poisson’s ratio and decrease of dynamic elastic modulus, and the former six water-rock cycle degradation effects are particularly obvious. Secondly, the numerical analog computation analysis of dynamic response in typical bank slope shows that as the water-rock interaction period is increased, the dynamic response of the slope hydro-fluctuation belt zone increases gradually, while the other parts weaken. Thirdly, under the long-term water-rock interaction process, the hydro-fluctuation belt zone gradually becomes a “soft layer” which is sensitive to the earthquake effect and dynamic response, resulting in a direct influence on long-term seismic performance of the bank slope. Therefore, it is necessary to make better protection for the bank slope hydro-fluctuation belt zone.

scholarly journals Influence of Rib Stiffness and Limited Long-Term Junction Strength on Geogrid Performance

2019 ◽  
Vol 7 (2) ◽  
pp. 175-190
Author(s):  
Werner Müller ◽  
Andreas Wöhlecke
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Numerical Approach ◽  
Reinforced Soil ◽  
Analytic Approach ◽  
Tensile Shear ◽  
Long Term Behavior ◽  
Longitudinal And Transverse Ribs

Abstract The description of the behavior of geogrids in reinforced soil constructions usually ignores long-term behavior and possible failure modes of junctions between longitudinal and transverse ribs. Two proposals have been made during recent years to overcome this drawback. The first analytic approach applies only to rigid geogrids and assumes a specific tensile-shear failure mode of geogrid junctions. The second numerical approach applies also for non-rigid geogrids and takes into account different modes of junction failure. This note discusses the two approaches focusing on the effects of rib stiffness and limited strength, different failure modes and degradation of junctions. It is shown that the mentioned effects should be considered in geogrid design, because they may alter significantly the long-term geogrid performance.

scholarly journals Circular Intermediates of Recombinant Adeno-Associated Virus Have Defined Structural Characteristics Responsible for Long-Term Episomal Persistence in Muscle Tissue

1998 ◽  
Vol 72 (11) ◽  
pp. 8568-8577 ◽  
Author(s):  
Dongsheng Duan ◽  
Prerna Sharma ◽  
Jusan Yang ◽  
Yongping Yue ◽  
Lorita Dudus ◽  
...  
Keyword(s):  
Muscle Tissue ◽  
Structural Characteristics ◽  
Shuttle Vector ◽  
Fold Increase ◽  
Structural Features ◽  
Nonviral Gene Delivery ◽  
Adeno Associated Virus ◽  
Great Utility ◽  
The Stability

ABSTRACT Adeno-associated viral (AAV) vectors have demonstrated great utility for long-term gene expression in muscle tissue. However, the mechanisms by which recombinant AAV (rAAV) genomes persist in muscle tissue remain unclear. Using a recombinant shuttle vector, we have demonstrated that circularized rAAV intermediates impart episomal persistence to rAAV genomes in muscle tissue. The majority of circular intermediates had a consistent head-to-tail configuration consisting of monomer genomes which slowly converted to large multimers of >12 kbp by 80 days postinfection. Importantly, long-term transgene expression was associated with prolonged (80-day) episomal persistence of these circular intermediates. Structural features of these circular intermediates responsible for increased persistence included a DNA element encompassing two viral inverted terminal repeats (ITRs) in a head-to-tail orientation, which confers a 10-fold increase in the stability of DNA following incorporation into plasmid-based vectors and transfection into HeLa cells. These studies suggest that certain structural characteristics of AAV circular intermediates may explain long-term episomal persistence with this vector. Such information may also aid in the development of nonviral gene delivery systems with increased efficiency.

scholarly journals Damage Degree analysis of storage failure modes for plastic encapsulated microelectronic devices

2021 ◽  
Vol 2132 (1) ◽  
pp. 012048
Author(s):  
Hang Ju ◽  
Shuang Liu
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Long Term Storage ◽  
Damage Degree ◽  
Risk Ranking ◽  
Lead Corrosion ◽  
Microelectronic Devices ◽  
Term Storage

Abstract After long-term storage, plastic sealing devices must have good performance when installed on the whole machine. Identifying the risk of failure mode and taking preventive measures before failure can effectively improve storage reliability. To ensure the quality of military products, this paper studies the storage failure modes of plastic sealed micro-electronic devices, and uses the method of FMECA to calculate the damage degree of each failure mode and determine the key failure modes. The case analysis shows that the damage degree of failure mode is ranked as external lead corrosion, aging of packaging material, chip corrosion and bonding ball corrosion. The evaluation result accords with the actual situation of the method. The improved FMECA model can better deal with the relative importance of risk factors, improve the accuracy of risk ranking, and quantify risks more reasonably.

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