The Effects of Water Content and Dry–Wet Cycles of Weak‐Interlayer Soil on Stability of Clastic Rock Slope

2021 ◽  
Author(s):  
Yingzi Xu ◽  
Xuhang Liao ◽  
Jian Li ◽  
Lihua Chen ◽  
Lin Li
Keyword(s):  
Water Content ◽  
Rock Slope ◽  
Clastic Rock ◽  
Weak Interlayer

scholarly journals Instability Process Model Test for Bedding Rock Slope with Weak Interlayer under Different Rainfall Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Zhongming He ◽  
Baolin Wang
Keyword(s):  
Plastic Flow ◽  
Model Test ◽  
Process Model ◽  
Rock Slope ◽  
Heavy Rain ◽  
Long Time ◽  
Weak Interlayer ◽  
Seepage Characteristics ◽  
Short Time ◽  
Bedding Rock Slope

The instability process of bedding rock slope with weak interlayer may be induced under rainfall infiltration conditions. Due to this, we conducted a research of model test for the instability process, based on the similarity theory. With use of the recent 50 years’ rainfall data of Changsha, China, we analyzed the seepage characteristics, mechanical characteristics, and deformation laws of the slope under the conditions of long-time heavy rain and short-time rainstorm, respectively. The test results show that the original seepage characteristics of the slope were changed by the existence of weak interlayer, presented the “double seepage” effect, resulted in the seepage characteristics of rock and soil in the shallow layer and weak interlayer of the slope showed a sickle “Γ” distribution, and the adjacent rock layer presented a curve-type “S” distribution. With the increase of rainfall duration, the weak interlayer gradually became muddy and softened, and then the plastic flow zone was formed locally. The stress concentration phenomenon was gradually generated in the weak interlayer due to the influence of the gravitational field of the upper rock mass. The large infiltration of rainwater led to the phenomenon of plastic flow extrusion of the slope at the weak interlayer extrusion. With the further penetration of the tensile cracks in the upper part of the weak interlayer, the slope had a large settlement displacement and gradually formed sliding shear deformation along the weak structural plane. Under the condition of equal rainfall amount, the condition of long-time heavy rain has a greater influence on the stability of the bedding rock slope with weak interlayer than that of short-time rainstorm. The failure form of slope could be divided into four stages: prechange stage, interlayer extrusion stage, slip-pull-fracture stage and plastic flow-shear failure stage.

Stability Analysis of Clastic Rock Slope with Mudstone Interlayer Under Rainfall Infiltration

2017 ◽  
Vol 35 (4) ◽  
pp. 1871-1883 ◽  
Author(s):  
Yingzi Xu ◽  
Jian Li ◽  
Haoran Fan ◽  
Lihua Chen ◽  
Yanlin Zhao ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Rock Slope ◽  
Rainfall Infiltration ◽  
Clastic Rock

scholarly journals Stability Analysis of Rock Slope with Multilayer Weak Interlayer

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jinglong Li ◽  
Bo Zhang ◽  
Bin Sui
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Double Layer ◽  
Rock Slope ◽  
Mechanical Characteristics ◽  
Soft Interlayer ◽  
Overall Stability ◽  
Weak Interlayer ◽  
The Stability ◽  
National Road

The existence of the weak interlayer of the rock slope changes its mechanical characteristics. To ensure the safety of the slope, it is necessary to analyze the overall stability of the slope. Taking the double-layer weak interlayer rock slope beside 318 National Road in Qiyue Mountain, Hubei Province, as an example, a slope model with a weak interlayer was established through GTS software, and the model was imported into FLAC3D for calculation, and the deformation of the slope by the double-layer soft interlayer was studied. The influence of characteristics and safety factors reveals the controlling effect of the double-layer weak interlayer on the stability of the slope and its failure mode. The potential sliding surface of the slope is determined to be the lower weak interlayer, and the weak interlayer after the anchor cable reinforcement is carried out. Numerical analysis shows that the reasonable application of anchor cables significantly improves slope stability. The research results can provide reference significance for slope stability analysis of similar projects.

scholarly journals Dynamic acceleration response of a rock slope with a horizontal weak interlayer in shaking table tests

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250418
Author(s):  
Hanxiang Liu ◽  
Tong Qiu ◽  
Qiang Xu
Keyword(s):  
Rock Slope ◽  
Time Lag ◽  
Shaking Table ◽  
Earthquake Ground Motion ◽  
Ratio Test ◽  
Deformation Characteristics ◽  
Strong Response ◽  
Input Amplitude ◽  
Topographic Amplification ◽  
Weak Interlayer

The weak interlayer in a rock slope often plays a significant role in seismic rockslides; however, the effect of weak interlayer on the seismic slope response and damage process is still not fully understood. This study presents a series of shaking test tests on two model slopes containing a horizontal weak interlayer with different thicknesses. A recorded Wenchuan earthquake ground motion was scaled to excite the slopes. Measurements from accelerometers embedded at different elevations of slope surface and slope interior were analyzed and compared. The effect of the weak interlayer thickness on the seismic response was highlighted by a comparative analysis of the two slopes in terms of topographic amplification, peak accelerations, and deformation characteristics as the input amplitude increased. It was found that the structure deterioration and nonlinear response of the slopes were manifested as a time lag of the horizontal accelerations in the upper slope relative to the lower slope and a reduction of resonant frequency and Fourier spectral ratio. Test results show that under horizontal acceleration, both slopes exhibited significant topographic amplification in the upper half, and the difference in amplification between slope face and slope interior was more pronounced in Slope B (with a thin weak interlayer) than in Slope A (with a thick weak interlayer). A four-phased dynamic response process of both slopes was observed. Similar deformation characteristics including development of strong response zone and macro-cracks, vertical settlement, horizontal extrusion and collapse in the upper half were observed in both slopes as the input amplitude increased; however, the deformations were more severe in Slope B than in Slope A, suggesting an energy isolation effect of the thick interlayer in Slope A.

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

STEM measurement of subcellular water distributions

1993 ◽  
Vol 51 ◽  
pp. 568-569
Author(s):  
R.D. Leapman ◽  
S.Q. Sun ◽  
S-L. Shi ◽  
R.A. Buchanan ◽  
S.B. Andrews
Keyword(s):  
Water Content ◽  
Internal Standard ◽  
Dry Weight ◽  
Dry Mass ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Bulk Water ◽  
Inelastic Electron ◽  
Scanning Transmission ◽  
Annular Dark Field

Recent advances in rapid-freezing and cryosectioning techniques coupled with use of the quantitative signals available in the scanning transmission electron microscope (STEM) can provide us with new methods for determining the water distributions of subcellular compartments. The water content is an important physiological quantity that reflects how fluid and electrolytes are regulated in the cell; it is also required to convert dry weight concentrations of ions obtained from x-ray microanalysis into the more relevant molar ionic concentrations. Here we compare the information about water concentrations from both elastic (annular dark-field) and inelastic (electron energy loss) scattering measurements.In order to utilize the elastic signal it is first necessary to increase contrast by removing the water from the cryosection. After dehydration the tissue can be digitally imaged under low-dose conditions, in the same way that STEM mass mapping of macromolecules is performed. The resulting pixel intensities are then converted into dry mass fractions by using an internal standard, e.g., the mean intensity of the whole image may be taken as representative of the bulk water content of the tissue.

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